US4777097A

US4777097A - Composite material including alumina-silica short fiber reinforcing material and aluminum alloy matrix metal with moderate copper and magnesium contents

Info

Publication number: US4777097A
Application number: US07/007,790
Authority: US
Inventors: Masahiro Kubo; Tadashi Dohnomoto; Atsuo Tanaka; Hidetoshi Hirai
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 1986-01-31
Filing date: 1987-01-28
Publication date: 1988-10-11
Anticipated expiration: 2007-01-28
Also published as: AU6793287A; EP0235574A3; CA1335044C; AU591959B2; EP0235574A2; DE3765436D1; EP0235574B1

Abstract

A composite material is made from alumina-silica type short fibers embedded in a matrix of metal. The matrix metal is an alloy consisting essentially of from approximately 2% to approximately 6% of copper, from approximately 0.5% to approximately 3.5% of magnesium, and remainder substantially aluminum. The short fibers have a composition of from about 35% to about 80% of Al₂ O₃ and from about 65% to about 20% of SiO₂ with less than about 10% of other included constituents, and may be either amorphous or crystalline, in the latter case optionally containing a proportion of the mullite crystalline form. The fiber volume proportion of the alumina-silica type short fibers is between approximately 5% and approximately 50%, and may more desirably be between approximately 5% and approximately 40%. If the alumina-silica short fibers are formed from amorphous alumina-silica material, the magnesium content of the aluminum alloy matrix metal may desirably be between approximately 0.5% and approximately 3%. And, in the desirable case that the fiber volume proportion of the alumina-silica type short fibers is between approximately 30% and approximately 40%, then the copper content of the aluminum alloy matrix metal is desired to be between approximately 2% and approximately 5.5%.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a composite material made up from reinforcing fibers embedded in a matrix of metal, and more particularly relates to such a composite material utilizing alumina-silica type short fiber material as the reinforcing fiber material, and aluminum alloy as the matrix metal, i.e. to an alumina-silica short fiber reinforced aluminum alloy.

Further, the present inventors wish hereby to attract the attention of the examining authorities to copending patent application Ser. Nos. 868,541; 868,542; 868,750; 895,811; 901,196; 911,880; and 001,924 which may be considered to be material to the examination of the present patent application.

As fiber reinforced aluminum alloys related to the present invention, there have been disclosed in the following U.S. patent applications filed by an Applicant the same as the Applicant of the parent Japanese patent applications of which Convention priority is being claimed for the present patent application--Ser. Nos. (1) 868,542; (2) 868,750; and (3) 868,541--respectively: (1) a composite material including silicon carbide short fibers in a matrix of aluminum alloy having a copper content of from approximately 2% to approximately 6%, a magnesium content of from approximately 2% to approximately 4%, and remainder substantially aluminum, with the volume proportion of said silicon carbide short fibers being from approximately 5% to approximately 50%; (2) a composite material including alumina short fibers in a matrix of aluminum alloy having a copper content of from approximately 2% to approximately 6%, a magnesium content of from approximately 0.5% to approximately 4%, and remainder substantially aluminum, with the volume proportion of alumina short fibers being from approximately 5% to approximately 50%, and (3) a composite material including silicon carbide short fibers in a matrix of aluminum alloy having a copper content of from approximately 2% to 6%, a magnesium content of from approximately 0% to approximately 2%, and remainder substantially aluminum, with the volume proportion of said silicon carbide short fibers being from approximately 5% to approximately 50%. However, it is not hereby intended to admit any of the above identified documents as prior art to the present patent application except to the extent in any case mandated by applicable law.

In the prior art, the following aluminum alloys of the cast type and of the wrought type have been utilized as matrix metal for a composite material:

Cast type aluminum alloys

JIS standard AC8A (from about 0.8% to about 1.3% Cu, from about 11.0% to about 13.0% Si, from about 0.7% to about 1.3% Mg, from about 0.8% to about 1.5% Ni, remainder substantially Al)

JIS standard AC8B (from about 2.0% to about 4.0% Cu, from about 8.5% to about 10.5% Si, from about 0.5% to about 1.5% Mg, from about 0.1% to about 1% Ni, remainder substantially Al)

JIS standard AC4C (Not more than about 0.25% Cu, from about 6.5% to about 7.5% Si, from about 0.25% to about 0.45% Mg, remainder substantially Al)

AA standard A201 (from about 4% to about 5% Cu, from about 0.2% to about 0.4% Mn, from about 0.15% to about 0.35% Mg, from about 0.15% to about 0.35% Ti, remainder substantially Al)

AA standard A356 (from about 6.5% to about 7.5% Si, from about 0.25% to about 0.45% Mg, not more than about 0.2% Fe, not more than about 0.2% Cu, remainder substantially Al)

Al--from about 2% to about 3% Li alloy (DuPont).

Wrought type aluminum alloys

JIS standard 6061 (from about 0.4% to about 0.8% Si, from about 0.15% to about 0.4% Cu, from about 0.8% to about 1.2% Mg, from about 0.04% to about 0.35% Cr, remainder substantially Al)

JIS standard 5056 (not more than about 0.3% Si, not more than about 0.4% Fe, not more than about 0.1% Cu, from about 0.05% to about 0.2% Mn, from about 4.5% to about 5.6% Mg, from about 0.05% to about 0.2% Cr, not more than about 0.1% Zn, remainder substantially Al)

JIS standard 7075 (not more than about 0.4% Si, not more than about 0.5% Fe, from about 1.2% to about 2.0% Cu, not more than about 0.3% Mn, from about 2.1% to about 2.9% Mg, from about 0.18% to about 0.28% Cr, from about 5.1% to about 6.1% Zn, about 0.2% Ti, remainder substantially Al).

Previous research relating to composite materials incorporating aluminum alloys as their matrix metals has generally been carried out from the point of view and with the object of improving the strength and so forth of existing aluminum alloys without changing their composition, and therefore these aluminum alloys conventionally used in the manufacture of such prior art composite materials have not necessarily been of the optimum composition in relation to the type of reinforcing fibers utilized therewith to form a composite material, and therefore, in the case of using one or the other of such conventional above mentioned aluminum alloys as the matrix metal for a composite material, the optimization of the mechanical characteristics, and particularly of the strength, of the composite material using such an aluminum alloy as matrix metal has not heretofore been satisfactorily attained.

SUMMARY OF THE INVENTION

The inventors of the present application have considered the above mentioned problems in composite materials which use such conventional aluminum alloys as matrix metal, and in particular have considered the particular case of a composite material which utilizes alumina-silica type short fibers as reinforcing fibers, since such alumina-silica type short fibers, among the various reinforcing fibers used conventionally in the manufacture of a fiber reinforced metal composite material, are relatively inexpensive, have particularly high strength, and are exceedingly effective in improving the high temperature stability and the strength of the composite material. And the present inventors, as a result of various experimental researches to determine what composition of the aluminum alloy to be used as the matrix metal for such a composite material is optimum, have discovered that an aluminum alloy having a content of copper and a content of magnesium within certain limits, and containing substantially no silicon, nickel, zinc, and so forth is optional as matrix metal, particularly in view of the bending strength characteristics of the resulting composite material. The present invention is based on the knowledge obtained from the results of the various experimental researches carried out by the inventors of the present application, as will be detailed later in this specification.

Accordingly, it is the primary object of the present invention to provide a composite material utilizing alumina-silica type short fibers as reinforcing material and aluminum alloy as matrix metal, which enjoys superior mechanical characteristics such as bending strength.

It is a further object of the present invention to provide such a composite material utilizing alumina-silica type short fibers as reinforcing material and aluminum alloy as matrix metal, which is cheap.

It is a further object of the present invention to provide such a composite material utilizing alumina-silica type short fibers as reinforcing material and aluminum alloy as matrix metal, which, for similar values of mechanical characteristics such as bending strength, can incorporate a lower volume proportion of reinforcing fiber material than prior art such composite materials.

It is a further object of the present invention to provide such a composite material utilizing alumina-silica type short fibers as reinforcing material and aluminum alloy as matrix metal, which is improved over prior art such composite materials as regards machinability.

It is a further object of the present invention to provide such a composite material utilizing alumina-silica type short fibers as reinforcing material and aluminum alloy as matrix metal, which is improved over prior art such composite materials as regards workability.

It is a further object of the present invention to provide such a composite material utilizing alumina-silica type short fibers as reinforcing material and aluminum alloy as matrix metal, which has good characteristics with regard to amount of wear on a mating member.

It is a yet further object of the present invention to provide such a composite material utilizing alumina-silica type short fibers as reinforcing material and aluminum alloy as matrix metal, which is not brittle.

It is a yet further object of the present invention to provide such a composite material utilizing alumina-silica type short fibers as reinforcing material and aluminum alloy as matrix metal, which is durable.

It is a yet further object of the present invention to provide such a composite material utilizing alumina-silica type short fibers as reinforcing material and aluminum alloy as matrix metal, which has good wear resistance.

It is a yet further object of the present invention to provide such a composite material utilizing alumina-silica type short fibers as reinforcing material and aluminum alloy as matrix metal, which has good uniformity.

According to the most general aspect of the present invention, these and other objects are attained by a composite material comprising a mass of alumina-silica short fibers embedded in a matrix of metal, said alumina-silica short fibers having a composition of from about 35% to about 80% of Al₂ O₃ and from about 65% to about 20% of SiO₂ with less than about 10% of other included constituents; said matrix metal being an alloy consisting essentially of from approximately 2% to approximately 6% of copper, from approximately 0.5% to approximately 3.5% of magnesium, and remainder substantially aluminum; and the volume proportion of said alumina-silica short fibers being from about 5% to about 50%. Optionally, said alumina-silica short fibers may have a composition of from about 35% to about 65% of Al₂ O₃ and from about 65% to about 35% of SiO₂ with less than about 10% of other included constituents; or, alternatively, said alumina-silica short fibers may have a composition of from about 65% to about 80% of Al₂ O₃ and from about 35% to about 20% of SiO₂ with less than about 10% of other included constituents.

According to the present invention as described above, as reinforcing fibers there are used alumina-silica type short fibers, optionally having a relatively high content of Al₂ O₃, which have high strength, and are exceedingly effective in improving the high temperature stability and strength of the resulting composite material, and as matrix metal there is used an aluminum alloy with a copper content of from approximately 2% to approximately 6%, a magnesium content of from approximately 0.5% to approximately 2%, and the remainder substantially aluminum, and the volume proportion of the alumina-silica short fibers is desirably from approximately 5% to approximately 50%, whereby, as is clear from the results of experimental research carried out by the inventors of the present application as will be described below, a composite material with superior mechanical characteristics such as strength can be obtained.

Preferably, the fiber volume proportion of said short fibers may be between approximately 5% and approximately 40%. Even more preferably, the fiber volume proportion of said short fibers may be between approximately 30% and approximately 40%, with the copper content of said aluminum alloy matrix metal being between approximately 2% and approximately 5.5%. The short fibers may be composed of amorphous alumina-silica material; or, alternatively, said short fibers may be crystalline, and optionally may have a substantial mullite crystalline content.

Also according to the present invention, in cases where it is satisfactory if the same degree of strength as a conventional alumina-silica type short fiber reinforced aluminum alloy is obtained, the volume proportion of alumina-silica type short fibers in a composite material according to the present invention may be set to be lower than the value required for such a conventional composite material, and therefore, since it is possible to reduce the amount of alumina-silica short fibers used, the machinability and workability of the composite material can be improved, and it is also possible to reduce the cost of the composite material. Further, the characteristics with regard to wear on a mating member will be improved.

As will become clear from the experimental results detailed hereinafter, when copper is added to aluminum to make the matrix metal of the composite material according to the present invention, the stength of the aluminum alloy matrix metal is increased and thereby the strength of the composite material is improved, but that effect is not sufficient if the copper content is less than 2%, whereas if the copper content is more than 6% the composite material becomes very brittle, and has a tendency rapidly to disintegrate. Therefore the copper content of the aluminum alloy used as matrix metal in the composite material of the present invention is required to be in the range of from approximately 2% to approximately 6%, and more preferably is desired to be in the range of from approximately 2% to approximately 5.5%.

Furthermore, oxides are inevitably always present on the surface of such alumina-silica short fibers used as reinforcing fibers, and if as is contemplated in the above magnesium, which has a strong tendency to form as oxide, is contained within the molten matrix metal, such magnesium will react with the oxides on the surfaces of the alumina-silica short fibers, and reduce the surfaces of the alumina-silica short fibers, as a result of which the affinity of the molten matrix metal and the alumina-silica short fibers will be improved, and by this means the strength of the composite material will be improved with an increase in the content of magnesium, as experimentally has been established as will be described in the following up to a magnesium content of approximately 2% to 3%. If however the magnesium content exceeds approximately 3.5%, as will also be described in the following, the strength of the composite material decreases rapidly. Therefore the magnesium content of the aluminum alloy used as matrix metal in the composite material of the present invention is desired to be from approximately 0.5% to approximately 3.5%, and preferably from approximately 0.5% to approximately 3%, and even more preferably from approximately 1.5% to approximately 3%.

Furthermore, in a composite material with an aluminum alloy of the above composition as matrix metal, as also will become clear from the experimental researches given hereinafter, if the volume proportion of the alumina-silica type short fibers is less than 5%, a sufficient strength cannot be obtained, and if the volume proportion of the alumina-silica type short fibers exceeds 40% and particularly if it exceeds 50% even if the volume proportion of the alumina-silica type short fibers is increased, the stength of the composite material is not very significantly improved. Also, the wear resistance of the composite material increases with the volume proportion of the alumina-silica type short fibers, but when the volume proportion of the alumina-silica type short fibers is in the range from zero to approximately 5% said wear resistance increases rapidly with an increase in the volume proportion of the alumina-silica type short fibers, whereas when the volume proportion of the alumina-silica type short fibers is in the range of at least approximately 5%, the wear resistance of the composite material does not very significantly increase with an increase in the volume proportion of said alumina-silica type short fibers. Therefore, according to one characteristic of the present invention, the volume proportion of the alumina-silica type short fibers is required to be in the range of from approximately 5% to approximately 50%, and preferably is required to be in the range of from approximately 5% to approximately 40%.

The alumina-silica short fibers in the composite material of the present invention may be made either of amorphous alumina-silica short fibers or of crystalline alumina-silica short fibers (alumina-silica short fibers including mullite crystals (3Al₂ O₃.2SiO₂)), and in the case that crystalline alumina silica short fibers are used as the alumina-silica short fibers, if the aluminum alloy has the above described composition, then, irrespective of the amount of the mullite crystals in the crystalline alumina-silica fibers, compared to the case that aluminum alloys of other compositions are used as matrix metal, the stength of the composite material can be improved.

As a result of other experimental research carried out by the inventors of the present application, regardless of whether the alumina-silica short fibers are formed of amorphous alumina-silica material or are formed of crystalline alumina-silica material, when the volume proportion of the alumina-silica short fibers is in the relatively high portion of the above described desirable range, that is to say is from approximately 30% to approximately 40%, it is preferable that the copper content of the aluminum alloy should be from approximately 2% to approximately 5.5%. Therefore, according to another detailed characteristic of the present invention, when the volume proportion of the alumina-silica short fibers is from approximately 30% to approximately 40%, the copper content of the aluminum alloy should be from approximately 2% to approximately 5.5%.

Also when amorphous alumina-silica short fibers are used as the alumina-silica short fibers, it is preferable for the magnesium content to be from approximately 0.5% to approximately 3%. Therefore, according to yet another detailed characteristic of the present invention, when for the alumina-silica short fibers there are used amorphous alumina-silica short fibers, the magnesium content of the aluminum alloy should be from approximately 0.5% to approximately 3%, and, when the volume proportion of said amorphous alumina-silica short fibers is from approximately 30% to 40%, the copper content of the aluminum alloy should be from approximately 2% to approximately 5.5% and the magnesium content should be from approximately 0.5% to approximately 3%.

If, furthermore, the copper content of the aluminum alloy used as matrix metal of the composite material of the present invention has a relatively high value, if there are unevennesses in the concentration of the copper or the magnesium within the aluminum alloy, the portions where the copper concentration or the magnesium concentration is high will be brittle, and it will not therefore be possible to obtain a uniform matrix metal or a composite material of good and uniform quality. Therefore, according to another detailed characteristic of the present invention, in order that the concentration of copper within the aluminum alloy matrix metal should be uniform, such a composite material of which the matrix metal is aluminum alloy of which the copper content is at least 0.5% and is less than 3.5% is subjected to liquidizing processing for from about 2 hours to about 8 hours at a temperature of from about 480° C. to about 520° C., and is preferably further subjected to aging processing for about 2 hours to about 8 hours at a temperature of from about 150° C. to 200° C.

Further, the alumina-silica short fibers used in the composite material of the present invention may either be alumina-silica non continuous fibers or may be alumina-silica continuous fibers cut to a predetermined length. Also, the fiber length of the alumina-silica type short fibers is preferably from approximately 10 microns to approximately 7 cm, and particularly is from approximately 10 microns to approximately 5 cm, and the fiber diameter is preferably from approximately 1 micron to approximately 30 microns, and particularly is from approximately 1 microns to approximately 25 microns.

Furthermore, when the composition of the matrix metal is determined as specified above, according to the present invention, since a composite material of high strength is obtained irrespective of the orientation of the alumina-silica fibers, the fiber orientation may be any of, for example, one directional fiber orientation, two dimensional random fiber orientation, or three dimensional random fiber orientation, but, in a case where high strength is required in a particular direction, then in cases where the fiber orientation is one directional random fiber orientation or two dimensional random fiber orientation, it is preferable for the particular desired high stength direction to be the direction of such one directional orientation, or a direction parallel to the plane of such two dimensional random fiber orientation.

It should be noted that in this specification all percentages, except in the expression of volume proportion of reinforcing fiber material, are percentages by weight, and in expressions of the composition of an aluminum alloy, "substantially aluminum" means that, apart from aluminum, copper and magnesium, the total of the inevitable metallic elements such as silicon, iron, zinc, manganese, nickel, titanium, and chromium included in the aluminum alloy used as matrix metal is not more than about 1%, and each of said impurity type elements individually is not present to more than about 0.5%. Further, in expressions relating to the composition of the alumina-silica type short fibers, the expression "substantially SiO₂ " means that, apart from the Al₂ O₃ and the SiO₂ making up the alumina-silica short fibers, other elements are present only to such extents as to constitute impurities. It should further be noted that, in this specification, in descriptions of ranges of compositions, temperatures and the like, the expressions "at least", "not less than", "at most", "no more than", and "from . . . to . . . " and so on are intended to include the boundary values of the respective ranges.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with respect to the preferred embodiments thereof, and with reference to the illustrative drawings appended hereto, which however are provided for the purposes of explanation and exemplification only, and are not intended to be limitative of the scope of the present invention in any way, since this scope is to be delimited solely by the accompanying claims. With relation to the figures, spatial terms are to be understood as referring only to the orientation on the drawing paper of the illustrations of the relevant parts, unless otherwise specified; like reference numerals, unless otherwise so specified, denote the same parts and gaps and spaces and so on in the various figures; and:

FIG. 1 is a set of graphs in which magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a first group of the first set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing crystalline alumina-silica short fiber material, containing approximately 65% Al₂ O₃ and of average fiber length approximately 1 mm, was approximately 20%), each said graph showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 2 is a set of graphs, similar to FIG. 1 for the first group of said first set of preferred embodiments, in which magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a second group of said first set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing crystalline alumina-silica short fiber material, again containing approximately 65% Al₂ O₃, was approximately 10%), each said graph again showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 3 is a set of graphs, similar to FIG. 1 for the first group of said first set of preferred embodiments and to FIG. 2 for the second group of said first preferred embodiment set, in which magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a third group of said first set of preferred embodiments of the material of the present (in which the volume proportion of reinforcing crystalline alumina-silica short fiber material, again containing approximately 65% Al₂ O₃, was now approximately 5%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 4 is a set of graphs, similar to FIGS. 1, 2, and 3 for the first through the third groups of said first set of preferred embodiments respectively, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a first group of the second set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing crystalline alumina-silica short fiber material, again containing approximately 65% Al₂ O₃, was now approximately 40%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 5 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments and to FIG. 4 for the first group of the second set of preferred embodiments respectively, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a second group of said second set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing crystalline alumina-silica short fiber material, again containing approximately 65% Al₂ O₃, was now approximately 30%), each said graph similarly showing the relation betwen magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 6 is a set of graphs, similar to FIGS. 1, 2, and 3 for the first through the third groups of said first set of preferred embodiments respectively and to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a first group of the third set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing crystalline alumina-silica short fiber material, now containing approximately 49% Al₂ O₃, was now approximately 30%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 7 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, and to FIG. 4 for the first group of said third preferred embodiment set respectively, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a second group of said third set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing crystalline alumina-silica short fiber material, again now containing approximately 49% Al₂ O₃, was now approximately 10%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 8 is a set of graphs, similar to FIGS. 1, 2, and 3 for the first through the third groups of said first set of preferred embodiments respectively, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, and to FIGS. 6 and 7 for the third preferred embodiment set, respectively, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a first group of the fourth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing crystalline alumina-silica short fiber material, now containing approximately 35% Al₂ O₃, was now approximately 30%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 9 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, and to FIG. 8 for the first group of this fourth preferred embodiment set respectively, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a second group of said fourth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing crystalline alumina-silica short fiber material, again now containing approximately 35% Al₂ O₃, was now approximately 10%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 10 is a set of graphs, similar to FIGS. 1, 2, and 3 for the first through the third groups of the first set of preferred embodiments respectively, to FIGS. 4 and 5 for the first and second groups of the second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, and to FIGS. 8 and 9 for the fourth preferred embodiment set, respectively, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a test group of the fifth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing, now amorphous, alumina-silica short fiber material, containing approximately 49% Al₂ O₃, was approximately 20%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 11 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, and to FIG. 10 for the first group of this fifth preferred embodiment set respectively, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a second group of said fifth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing, now amorphous, alumina-silica short fiber material, containing approximately 49% Al₂ O₃, was now approximately 10%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 12 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, and to FIGS. 10 and 11 for the first and second groups of this fifth preferred embodiment set, respectively, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a third group of said fifth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing, now amorphous, alumina-silica short fiber material, containing approximately 49% Al₂ O₃, was now approximately 5%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 13 is a set of graphs, similar to FIGS. 1, 2, and 3 for the first through the third groups of the first set of preferred embodiments respectively, to FIGS. 4 and 5 for the first and second groups of the second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, and to FIGS. 10 through 12 for the fifth preferred embodiment set, respectively, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strengh tests for a first group of the sixth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing amorphous alumina-silica short fiber material, again containing approximately 49% Al₂ O₃, was now approximately 40%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 14 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, to FIGS. 10 through 12 for the fifth preferred embodiment set, and to FIG. 13 for the first group of this sixth preferred embodiment set, respectively, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a second group of said sixth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing amorphous alumina-silica short fiber material, again containing approximately 49% Al₂ O₃, was now approximately 30%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 15 is a set of two graphs relating to two sets of tests in which the fiber volume proportions of reinforcing alumina-silica short fiber materials of two different types were varied, in which said reinforcing fiber proportion in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for certain ones of a seventh set of preferred embodiments of the material of the present invention, said graphs showing the relation between volume proportion of the reinforcing alumina-silica short fiber material and bending strength of certain test pieces of the composite material;

FIG. 16 is a graph relating to the eighth set of preferred embodiments, in which mullite crystalline content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for various composite materials having crystalline alumina-silica short fiber material with varying amounts of the mullite crystalline form therein as reinforcing material and an alloy containing approximately 4% of copper, approximately 2% of magnesium, and remainder substantially aluminum as matrix metal, and showing the relation between the mullite crystalline percentage of the reinforcing short fiber material of the composite material test pieces and their bending strengths;

FIG. 17 is a perspective view of a preform made of alumina-silica type short fiber material, with said alumina-silica type short fibers being aligned substantially randomly in two dimensions in the planes parallel to its larger two faces while being stacked in the third dimension perpendicular to said planes and said faces, for incorporation into composite materials according to various preferred embodiments of the present invention;

FIG. 18 is a perspective view, showing said preform made of alumina-silica type non continuous fiber material enclosed in a stainless steel case both ends of which are open, for incorporation into said composite materials;

FIG. 19 is a schematic sectional diagram showing a high pressure casting device in the process of performing high pressure casting for manufacturing a composite material with the alumina-silica type short fiber material preform material of FIGS. 18 and 19 (enclosed in its stainless steel case) being incorporated in a matrix of matrix metal;

FIG. 20 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, to FIGS. 10 through 12 for the fifth preferred embodiment set, and to FIGS. 13 and 14 for the sixth preferred embodiment set, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a first group of the ninth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing crystalline alumina-silica short fiber material, now containing approximately 72% Al₂ O₃, was now approximately 20%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 21 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, to FIGS. 10 through 12 for the fifth preferred embodiment set, to FIGS. 13 and 14 for the sixth preferred embodiment set, and to FIG. 20 for the first group of this ninth preferred embodiment set, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a second group of said ninth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing crystalline alumina-silica short fiber material, again now containing approximately 72% Al₂ O₃, was now approximately 10%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 22 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, to FIGS. 10 through 12 for the fifth preferred embodiment set, to FIGS. 13 and 14 for the sixth preferred embodiment set, and to FIGS. 20 and 21 for the first and the second group of this ninth preferred embodiment set, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a third group of said ninth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing crystalline alumina-silica short fiber material, again now containing approximately 72% Al₂ O₃, was now approximately 5%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 23 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, to FIGS. 10 through 12 for the fifth preferred embodiment set, to FIGS. 13 and 14 for the sixth preferred embodiment set, and to FIGS. 20 through 22 for the ninth preferred embodiment set, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a first group of a tenth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing crystalline alumina-silica short fiber material, again now containing approximately 72% Al₂ O₃, was now approximately 40%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 24 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, to FIGS. 10 through 12 for the fifth preferred embodiment set, to FIGS. 13 and 14 for the sixth preferred embodiment set, to FIGS. 20 through 22 for the ninth preferred embodiment set, and to FIG. 23 for the first group of this tenth preferred embodiment set, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a second group of said tenth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing crystalline alumina-silica short fiber material, again now containing approximately 72% Al₂ O₃, was now approximately 30%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 25 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodients, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, to FIGS. 10 through 12 for the fifth preferred embodiment set, to FIGS. 13 and 14 for the sixth preferred embodiment set, to FIGS. 20 through 22 for the ninth preferred embodiment set, and to FIGS. 23 and 24 for the tenth preferred embodiment set, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for an eleventh set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing, now amorphous, alumina-silica short fiber material, again now containing approximately 72% Al₂ O₃ and now of average fiber length approximately 2 mm, was now approximately 10%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 26 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, to FIGS. 10 through 12 for the fifth preferred embodiment set, to FIGS. 13 and 14 for the sixth preferred embodiment set, to FIGS. 20 through 22 for the ninth preferred embodiment set, to FIGS. 23 and 24 for the tenth preferred embodiment set, and to FIG. 25 for the eleventh preferred embodiment set, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a twelfth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing amorphous alumina-silica short fiber material, again now containing approximately 72% Al₂ O₃ and now of average fiber length approximately 0.8 mm, was now approximately 30%), each said graph similarly showing the relation between magnesium content and being strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 27 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, to FIGS. 10 through 12 for the fifth preferred embodiment set, to FIGS. 13 and 14 for the sixth preferred embodiment set, to FIGS. 20 through 22 for the ninth preferred embodiment set, to FIGS. 23 and 24 for the tenth preferred embodiment set, and to FIGS. 25 and 26 for the eleventh and twelfth preferred embodiment sets respectively, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a thirteenth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing, now crystalline, alumina-silica short fiber material, now containing approximately 77% Al₂ O₃ and now of average fiber length approximately 1.5 mm, was now approximately 10%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 28 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, to FIGS. 10 through 12 for the fifth preferred embodiment set, to FIGS. 13 and 14 for the sixth preferred embodiment set, to FIGS. 20 through 22 for the ninth preferred embodiment set, to FIGS. 23 and 24 for the tenth preferred embodiment set, and to FIGS. 25 through 27 for the eleventh through the thirteenth preferred embodiment sets respectively, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a fourteenth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing, now amorphous, alumina-silica short fiber material, again containing approximately 77% Al₂ O₃ and now of average fiber length approximately 0.6 mm, was now approximately 30%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 29 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, to FIGS. 10 through 12 for the fifth preferred embodiment set, to FIGS. 13 and 14 for the sixth preferred embodiment set, to FIGS. 20 through 22 for the ninth preferred embodiment set, to FIGS. 23 and 24 for the tenth preferred embodiment set, and to FIGS. 25 through 28 for the eleventh through the fourteenth preferred embodiment sets respectively, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a fifteenth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing, now crystalline, alumina-silica short fiber material, now containing approximately 67% Al₂ O₃ and now of average fiber length approximately 0.3 mm, was again approximately 30%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 30 is a set of graphs, similar to FIGS. 1, 2, and 3 for the three groups of the first set of preferred embodiments, to FIGS. 4 and 5 for the first and second groups of said second preferred embodiment set, to FIGS. 6 and 7 for the third preferred embodiment set, to FIGS. 8 and 9 for the fourth preferred embodiment set, to FIGS. 10 through 12 for the fifth preferred embodiment set, to FIGS. 13 and 14 for the sixth preferred embodiment set, to FIGS. 20 through 22 for the ninth preferred embodiment set, to FIGS. 23 and 24 for the tenth preferred embodiment set, and to FIGS. 25 through 29 for the eleventh through the fifteenth preferred embodiment sets respectively, in which again magnesium content in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for a sixteenth set of preferred embodiments of the material of the present invention (in which the volume proportion of reinforcing, now amorphous, alumina-silica short fiber material, again containing approximately 67% Al₂ O₃ and now of average fiber length approximately 1.2 mm, was now approximately 10%), each said graph similarly showing the relation between magnesium content and bending strength of certain composite material test pieces for a particular fixed percentage content of copper in the matrix metal of the composite material;

FIG. 31 is similar to FIG. 15, being a set of two graphs relating to two sets of tests in which the fiber volume proportions of reinforcing alumina-silica short fiber materials of two different types were varied, in which said reinforcing fiber proportion in percent is shown along the horizontal axis and bending strength in kg/mm² is shown along the vertical axis, derived from data relating to bending strength tests for certain ones of a seventeenth set of preferred embodiments of the material of the present invention, said graphs showing the relation between volume proportion of the reinforcing alumina-silica short fiber material and bending strength of certain test pieces of the composite material; and:

FIG. 32 is similar to FIG. 16, being a graph relating to the eighteenth set of preferred embodiments, in which mullite crystalline content in percent is shown along the horizontal axis and bending strength in kg/mm is shown along the vertical axis, derived from data relating to bending strength tests for various composite materials having crystalline alumina-silica short fiber material with varying amounts of the mullite crystalline form therein as reinforcing material and an alloy containing approximately 4% of copper, approximately 2% of magnesium, and remainder substantially aluminum as matrix metal, and showing the relation between the mullite crystalline percentage of the reinforcing short fiber material of the composite material test pieces and their bending strengths.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described with reference to the various preferred embodiments thereof. It should be noted that all of the tables referred to in this specification are to be found at the end of the specification and before the claims thereof: the present specification is arranged in such a manner in order to maximize ease of pagination. Further, the preferred embodiments of the present invention are conveniently divided into two groupings of sets thereof, as will be seen in what follows.

THE FIRST GROUPING OF PREFERRED EMBODIMENT SETS The First Set of Preferred Embodiments

In order to assess what might be the most suitable composition for an aluminum alloy to be utilized as matrix metal for a contemplated composite material of the type described in the preamble to this specification, the reinforcing material of which is to be, in this case, crystalline alumina-silica short fibers, the present inventors manufactured by using the high pressure casting method samples of various composite materials, utilizing as reinforcing material crystalline alumina-silica short fiber material, which in this case had composition about 65% Al₂ O₃ and remainder substantially SiO₂, with the mullite crystalline proportion contained therein being about 60%, and which had average fiber length about 1 mm and average fiber diameter about 3 microns, and utilizing as matrix metal Al-Cu-Mg type aluminum alloys of various compositions. Then the present inventors conducted evaluations of the bending strength of the various resulting composite material sample pieces.

First, a set of aluminum alloys designated as A1 through A56 were produced, having as base material aluminum and having various quantities of magnesium and copper mixed therewith, as shown in the appended Table 1; this was done by, in each case, combining an appropriate quantity of substantially pure aluminum metal (purity at least 99%), an appropriate quantity of substantially pure magnesium metal (purity at least 99%), and an appropriate quantity of a mother alloy of approximately 50% aluminum and approximately 50% copper. And three sets, each containing an appropriate number (actually, fifty-six), of alumina-silica short fiber material preforms were made by, in each case, subjecting a quantity of the above specified crystalline alumina-silica short fiber material to compression forming without using any binder. Each of these crystalline alumina-silica short fiber material preforms was, as schematically illustrated in perspective view in FIG. 17 wherein an exemplary such preform is designated by the reference numeral 2 and the crystalline alumina-silica short fibers therein are generally designated as 1, about 38×100×16 mm in dimensions, and the individual crystalline alumina-silica short fibers 1 in said preform 2 were oriented as overlapping in a two dimensionally random manner in planes parallel to the 38×100 mm plane while being stacked in the direction perpendicular to this plane. And the fiber volume proportion in a first set of said preforms 2 was approximately 20%, in a second set of said preforms 2 was approximately 10%, and in a third set of said preforms 2 was approximately 5%; thus, in all, there were a hundred and sixty eight such preforms.

Next, each of these crystalline alumina-silica short fiber material preforms 2 was subjected to high pressure casting together with an appropriate quantity of one of the aluminum alloys A1 through A56 described above, in the following manner. First, the preform 2 was was inserted into a stainless steel case 2a, as shown in perspective view in FIG. 18, which was about 38×100×16 mm in internal dimensions and had both of its ends open. After this, each of these stainless steel cases 2a with its preform 2 held inside it was heated up to a temperature of approximately 600° C., and then said preform 2 was placed within a mold cavity 4 of a casting mold 3, which itself had previously been preheated up to a temperature of approximately 250° C. Next, a quantity 5 of the appropriate one of the aluminum alloys A1 to A56 described above, molten and maintained at a temperature of approximately 700° C., was relatively rapidly poured into said mold cavity 4, so as to surround the preform 2 therein, and then as shown in schematic perspective view in FIG. 18 a pressure plunger 6, which itself had previously been preheated up to a temperature of approximately 200° C., and which closely cooperated with the upper portion of said mold cavity 4, was inserted into said upper mold cavity portion, and was pressed downwards by a means not shown in the figure so as to pressurize said molten aluminum alloy quantity 5 and said preform 2 to a pressure of approximately 1000 kg/cm². Thereby, the molten aluminum alloy was caused to percolate into the interstices of the alumina-silica short fiber material preform 2. This pressurized state was maintained until the quantity 5 of molten aluminum alloy had completely solidified, and then the pressure plunger 6 was removed and the solidified aluminum alloy mass with the stainless steel case 2a and the preform 2 included therein was removed from the casting mold 3, and the peripheral portion of said solidified aluminum alloy mass and also the stainless steel case 2a were machined away, leaving only a sample piece of composite material which had crystalline alumina-silica short fiber material as reinforcing material and the appropriate one of the aluminum alloys A1 through A56 as matrix metal. The volume proportion of crystalline alumina-silica short fiber material in each of the resulting composite material sample pieces thus produced from the first set of said preforms 2 was approximately 20%, in each of the resulting composite material sample pieces thus produced from the second set of said preforms 2 was approximately 10%, and in each of the resulting composite material sample pieces thus produced from the third set of said preforms 2 was approximately 5%.

Next the following post processing steps were performed on the composite material samples. First, irrespective of the value for the magnesium content: those of said composite material samples which incorporated an aluminum alloy matrix metal which had copper content less than about 2% were subjected to liquidizing processing at a temperature of approximately 530° C. for approximately 8 hours, and then were subjected to artificial aging processing at a temperature of approximately 160° C. for approximately 8 hours; and those of said composite material samples which incorporated an aluminum alloy matrix metal which had copper content of at least about 2% and less than about 3.5% were subjected to liquidizing processing at a temperature of approximately 500° C. for approximately 8 hours, and then were subjected to artificial aging processing at a temperature of approximately 160° C. for approximately 8 hours; while those of said composite material samples which incorporated an aluminum alloy matrix metal which had copper content more than about 3.5% and less than about 6.5% were subjected to liquidizing processing at a temperature of approximately 480° C. for approximately 8 hours, and then were subjected to artificial aging processing at a temperature of approximately 160° C. for approximately 8 hours. Then, in each set of cases, from each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there was cut a bending strength test piece of length approximately 50 mm, width approximately 10 mm, and thickness approximately 2 mm, with the planes of random fiber orientation extending parallel to the 50 mm×10 mm faces of said test pieces, and for each of these composite material bending strength test pieces a three point bending strength test was carried out, with a gap between supports of approximately 40 mm. In these bending strength test 5, the bending strength of the composite material bending strength test pieces was measured as the surface stress at breaking point M/Z (M is the bending moment at the breaking point, while Z is the cross section coefficient of the composite material bending strength test piece).

The results of these bending strength tests were as shown in the first three columns of the appended Table 2, and as summarized in the line graphs of FIGS. 1 through 3, which relate to the cases of fiber volume proportion being equal to 20%, 10%, and 5% respectively. The first through the third columns of Table 2 show, for the respective cases of 5%, 10%, and 20% volume proportion of the reinforcing crystalline alumina-silica fiber material, the values of the bending strength (in kg/mm²) for each of the test sample pieces A1 through A56. And each of the line graphs of FIG. 1 shows the relation between magnesium content (in percent) and the bending strength (in kg/mm²) shown along the vertical axis of those of said composite material test pieces having as matrix metals aluminum alloys with percentage content of magnesium as shown along the horizontal axis and with percentage content of copper fixed along said line graph, and having as reinforcing material the above specified crystalline alumina-silica fibers (Al₂ O₃ content approximately 65%) in volume proportion of 20%; each of the line graphs of FIG. 2 shows the relation between magnesium content (in percent) and the bending strength (in kg/mm²) shown along the vertical axis of those of said composite material test pieces having as matrix metals aluminum alloys with percentage content of magnesium as shown along the horizontal axis and with percentage content of copper fixed along said line graph, and having as reinforcing material the above specified crystalline alumina-silica fibers (Al₂ O₃ content approximately 65%) in volume proportion of 10%; and each of the line graphs of FIG. 3 shows the relation between magnesium content (in percent) and the bending strength (in kg/mm²) shown along the vertical axis of those of said composite material test pieces having as matrix metals aluminum alloys with percentage content of magnesium as shown along the horizontal axis and with percentage content of copper fixed along said line graph, and having as reinforcing material the above specified crystalline alumina-silica fibers (Al₂ O₃ content approximately 65%) in volume proportion of 5%.

From Table 2 and from FIGS. 1 through 3 it will be understood that for all of these composite materials, when as in these cases the volume proportion of the reinforcing crystalline alumina-silica short fiber material of these bending strength composite material test sample pieces was approximately 20%, approximately 10%, or approximately 5%, substantially irrespective of the magnesium content of the aluminum alloy matrix metal, when the copper content was either at the low extreme of approximately 1.5% or was at the high extreme of approximately 6.5%, the bending strength of the composite material test sample pieces had a relatively low value; and, substantially irrespective of the copper content of the aluminum alloy matrix metal, when the magnesium content was either at the lower value of approximately 0% or at the higher value of approximately 4%, the bending strength of the composite material test sample pieces had a relatively low value. Further, it will be seen that, when the magnesium content was in the range of from approximately 1% to approximately 3%, the bending strength of the composite material test sample pieces attained a substantially maximum value; and, when the magnesium content increased above or decreased below this range, then the bending strength of the composite material test sample pieces decreased gradually; while, when the magnesium content was either in the low range below approximately 0.5% or was in the high range above approximately 3.5%, the bending strength of the composite material test sample pieces reduced relatively suddenly with decrease (excluding the cases where the copper content of the matrix metal was approximately 6% or approximately 6.5%) or increase respectively of the magnesium content; and, when the magnesium content was approximately 4%, the bending strength of the composite material test sample pieces had substantially the same value, as when the magnesium content was approximately 0%.

From the results of these bending strength tests it will be seen that, in order to provide for a good and appropriate bending strength for a composite material having as reinforcing fiber material such crystalline alumina-silica short fibers with Al₂ O₃ content approximately 65% in volume proportions of approximately 20%, approximately 10%, and approximately 5%, and having as matrix metal an Al-Cu-Mg type aluminum alloy, with remainder substantially Al₂ O₃, it is preferable that the copper content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 2% to approximately 6% while the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 0.5% to approximately 3.5%.

THE SECOND SET OF PREFERRED EMBODIMENTS

Next, the present inventors manufactured further samples of various composite materials, again utilizing as reinforcing material the same crystalline alumina-silica short type fiber material, and utilizing as matrix metal substantially the same fifty six types of Al-Cu-Mg type aluminum alloys, but this time employing, for the one set, fiber volume proportions of approximately 40%, and, for another set, fiber volume proportions of approximately 30%. Then the present inventors again conducted evaluations of the bending strength of the various resulting composite material sample pieces.

First, a set of fifty six quantities of aluminum alloy material the same as those utilized in the first set of preferred embodiments were produced in the same manner as before, again having as base material aluminum and having various quantities of magnesium and copper mixed therewith. And an appropriate number (a hundred and twelve) of crystalline alumina-silica short type fiber material preforms were as before made by the method disclosed above with respect to the first set of preferred embodiments, one set of said crystalline alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 40%, and another set of said crystalline alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 30%, by contrast to the first set of preferred embodiments described above. These preforms had substantially the same dimensions as the preforms of the first set of preferred embodiments.

Next, substantially as before, each of these crystalline alumina-silica short fiber type material preforms was subjected to high pressure casting together with an appropriate quantity of one of the aluminum alloys A1 through A56 described above, utilizing operational parameters substantially as before. The solidified aluminum alloy mass with the preform included therein was then removed from the casting mold, and the peripheral portion of said solidified aluminum alloy mass and the stainless steel case were machined away, leaving only a sample piece of composite material which had crystalline alumina-silica short type fiber material as reinforcing material and the appropriate one of the aluminum alloys A1 through A56 as matrix metal. The volume proportion of crystalline alumina-silica short type fibers in each of the one set of the resulting composite material sample pieces was thus now approximately 40%, and in each of the other set of the resulting composite material sample pieces was thus now approximately 30%. And post processing steps were performed on the composite material samples, substantially as before. From each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there was cut a bending strength test piece of dimensions and parameters substantially as in the case of the first set of preferred embodiments, and for each of these composite material bending strength test pieces a bending strength test was carried out, again substantially as before.

The results of these bending strength tests were as shown in the last two columns of Table 2 and as summarized in the graphs of FIGS. 4 and 5, which relate to the cases of fiber volume proportion being equal to 40% and 30% respectively; thus, FIGS. 4 and 5 correspond to FIGS. 1 through 3 relating to the first set of preferred embodiments. In the graphs of FIGS. 4 and 5, there are again shown relations between magnesium content and the bending strength (in kg/mm²) of certain of the composite material test pieces, for percentage contents of copper fixed along the various lines thereof.

From Table 2 and from FIGS. 4 and 5 it will be understood that for all of these composite materials, when as in these cases the volume proportion of the reinforcing crystalline alumina-silica short fiber material of these bending strength composite material test sample pieces was approximately 40% or was approximately 30%, substantially irrespective of the magnesium content of the aluminum alloy matrix metal, when the copper content was either at the low extreme of approximately 1.5% or was at the high extreme of approximately 6.5%, the bending strength of the composite material test sample pieces had a relatively low value; and, substantially irrespective of the copper content of the aluminum alloy matrix metal, when the magnesium content was either at the lower value of approximately 0% or at the higher value of approximately 4%, the bending strength of the composite material test sample pieces had a relatively low value. Further, it will be seen that, when the magnesium content was in the range of from approximately 2% to approximately 3%, the bending strength of the composite material test sample pieces attained a substantially maximum value; and, when the magnesium content increased above or decreased below this range, then the bending strength of the composite material test sample pieces decreased gradually; while, when the magnesium content was either in the low range below approximately 0.5% or was in the high range above approximately 3.5%, the bending strength of the composite material test sample pieces reduced relatively suddenly with decrease (excluding the cases where the copper content of the matrix metal was approximately 6% or approximately 6.5%) or increase respectively of the magnesium content; and, when the magnesium content was approximately 4%, the bending strength of the composite material test sample pieces had substantially the same value, as when the magnesium content was approximately 0%.

From the results of these bending strength tests it will be seen that, in order to provide for a good and appropriate bending strength for a composite material having as reinforcing fiber material such crystalline alumina-silica short fibers with Al₂ O₃ content approximately 65% in volume proportion of approximately 40% and approximately 30% and having as matrix metal an Al-Cu-Mg type aluminum alloy, with remainder substantially Al₂ O₃, it is preferable that the copper content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 2% to approximately 6% and particularly should be in the range of from approximately 2% to approximately 5.5%, while the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 0.5% to approximately 3.5%.

THE THIRD SET OF PREFERRED EMBODIMENTS

For the third set of preferred embodiments of the present invention, a different type of reinforcing fiber was chosen. The present inventors manufactured by using the high pressure casting method samples of various composite materials, utilizing as matrix metal Al-Cu-Mg type aluminum alloys of various compositions, and utilizing as reinforcing material crystalline alumina-silica short fiber material, which in this case had composition about 49% Al₂ O₃ and remainder substantially SiO₂, with the mullite crystalline proportion contained therein again being about 60%, and which again had average fiber length about 1 mm and average fiber diameter about 3 microns. Then the present inventors conducted evaluations of the bending strength of the various resulting composite material sample pieces.

First, a set of fifty six quantities of aluminum alloy material the same as those utilized in the previously described sets of preferred embodiments were produced in the same manner as before, again having as base material aluminum and having various quantities of magnesium and copper mixed therewith. And an appropriate number (again a hundred and twelve) of crystalline alumina-silica short type fiber material preforms were as before made by the method disclosed above with respect to the first and second sets of preferred embodiments, one set of said crystalline alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 30%, and another set of said crystalline alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 10%, by contrast to the first and second sets of preferred embodiments described above. These preforms had substantially the same dimensions as the preforms of the first and second sets of preferred embodiments.

Next, substantially as before, each of these crystalline alumina-silica short fiber type material preforms was subjected to high pressure casting together with an appropriate quantity of one of the aluminum alloys A1 through A56 described above, utilizing operational parameters substantially as before. The solidified aluminum alloy mass with the preform included therein was then removed from the casting mold, and the peripheral portion of said solidified aluminum alloy mass and the stainless steel case were machined away, leaving only a sample piece of composite material which had crystalline alumina-silica short type fiber material as reinforcing material and the appropriate one of the aluminum alloys A1 through A56 as matrix metal. The volume proportion of crystalline alumina-silica short type fibers in each of the one set of the resulting composite material sample pieces was thus now approximately 30%, and in each of the other set of the resulting composite material sample pieces was thus now approximately 10%. And post processing steps were performed on the composite material samples, substantially as before. From each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there was cut a bending strength test piece of dimensions and parameters substantially as in the case of the first and second sets of preferred embodiments, and for each of these composite material bending strength test pieces a bending strength test was carried out, again substantially as before.

The results of these bending strength tests were as shown in Table 3 and as summarized in the graphs of FIGS. 6 and 7, which relate to the cases of fiber volume proportion being equal to 30% and 10% respectively; thus, FIGS. 6 and 7 correspond to FIGS. 1 through 3 relating to the first set of preferred embodiments and to FIGS. 4 and 5 relating to the second set of preferred embodiments. In the graphs of FIGS. 4 and 5, there are again shown relations between magnesium content and the bending strength (in kg/mm²) of certain of the composite material test pieces, for percentage contents of copper fixed along the various lines thereof.

From Table 3 and from FIGS. 6 and 7 it will be understood that for all of these composite materials, when as in these cases the volume proportion of the reinforcing crystalline alumina-silica short fiber material of these bending strength composite material test sample pieces was approximately 30% or was approximately 10%, substantially irrespective of the magnesium content of the aluminum alloy matrix metal, when the copper content was either at the low extreme of approximately 1.5% or was at the high extreme of approximately 6.5%, the bending strength of the composite material test sample pieces had a relatively low value; and, substantially irrespective of the copper content of the aluminum alloy matrix metal, when the magnesium content was either at the lower value of approximately 0% or at the higher value of approximately 4%, the bending strength of the composite material test sample pieces had a relatively low value. Further, it will be seen that, when the magnesium content was in the range of from approximately 2% to approximately 3%, the bending strength of the composite material test sample pieces attained a substantially maximum value; and, when the magnesium content increased above or decreased below this range, then the bending strength of the composite material test sample pieces decreased gradually; while, when the magnesium content was either in the low range below approximately 0.5% or was in the high range above approximately 3.5%, the bending strength of the composite material test sample pieces reduced relatively suddenly with decrease (excluding the cases where the copper content of the matrix metal was approximately 6% or approximately 6.5%) or increase respectively of the magnesium content; and, when the magnesium content was approximately 4%, the bending strength of the composite material test sample pieces had substantially the same value as, or at least not a greater value than, when the magnesium content was approximately 0%.

From the results of these bending strength tests it will be seen that, in order to provide for a good and appropriate bending strength for a composite material having as reinforcing fiber material such crystalline alumina-silica short fibers with Al₂ O₃ content approximately 49% in volume proportions of approximately 30% and approximately 10% and having as matrix metal an Al-Cu-Mg type aluminum alloy, with remainder substantially Al₂ O₃, it is preferable that the copper content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 2% to approximately 6%, while the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 0.5% to approximately 3.5%.

THE FOURTH SET OF PREFERRED EMBODIMENTS

For the fourth set of preferred embodiments of the present invention, again a different type of reinforcing fiber was chosen. The present inventors manufactured by using the high pressure casting method samples of various composite materials, utilizing as matrix metal Al-Cu-Mg type aluminum alloys of various compositions, and utilizing as reinforcing material crystalline alumina-silica short fiber material, which in this case had composition about 35% Al₂ O₃ and remainder substantially SiO₂, with the mullite crystalline proportion contained therein now being about 40%, and which again had average fiber length about 1 mm and average fiber diameter about 3 microns. Then the present inventors conducted evaluations of the bending strength of the various resulting composite material sample pieces.

First, a set of fifty six quantities of aluminum alloy material the same as those utilized in the previously described sets of preferred embodiments were produced in the same manner as before, again having as base material aluminum and having various quantities of magnesium and copper mixed therewith. And an appropriate number (again a hundred and twelve) of crystalline alumina-silica short type fiber material preforms were as before made by the method disclosed above with respect to the previously described sets of preferred embodiments, one set of said crystalline alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 30%, and another set of said crystalline alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 10%, by contrast to the various sets of preferred embodiments described above. These preforms had substantially the same dimensions as the preforms of the previously described sets of preferred embodiments.

Next, substantially as before, each of these crystalline alumina-silica short fiber type material preforms was subjected to high pressure casting together with an appropriate quantity of one of the aluminum alloys A1 through A56 described above, utilizing operational parameters substantially as before. The solidified aluminum alloy mass with the preform included therein was then removed from the casting mold, and the peripheral portion of said solidified aluminum alloy mass and the stainless steel case were machined away, leaving only a sample piece of composite material which had crystalline alumina-silica short type fiber material as reinforcing material and the appropriate one of the aluminum alloys A1 through A56 as matrix metal. The volume proportion of crystalline alumina-silica short type fibers in each of the one set of the resulting composite material sample pieces was thus now approximately 30%, and in each of the other set of the resulting composite material sample pieces was thus now approximately 10%. And post processing steps were performed on the composite material samples, substantially as before. From each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there was cut a bending strength test piece of dimensions and parameters substantially as in the case of the previously described sets of preferred embodiments, and for each of these composite material bending strength test pieces a bending strength test was carried out, again substantially as before.

The results of these bending strength tests were as shown in Table 4 and as summarized in the graphs of FIGS. 8 and 9, which relate to the cases of fiber volume proportion being equal to 30% and 10% respectively; thus, FIGS. 8 and 9 correspond to FIGS. 1 through 3 relating to the first set of preferred embodiments, to FIGS. 4 and 5 relating to the second set of preferred embodiments, and to FIGS. 6 and 7 relating to the third preferred embodiment set. In the graphs of FIGS. 8 and 9, there are again shown relations between magnesium content and the bending strength (in kg/mm²) of certain of the composite material test pieces, for percentage contents of copper fixed along the various lines thereof.

From Table 4 and from FIGS. 8 and 9 it will be understood that for all of these composite materials, when as in these cases the volume proportion of the reinforcing crystalline alumina-silica short fiber material of these bending strength composite material test sample pices was approximately 30% or was approximately 10%, substantially irrespective of the magnesium content of the aluminum alloy matrix metal, when the copper content was either at the low extreme of approximately 1.5% or was at the high extreme of approximately 6.5%, the bending strength of the composite material test sample pieces had a relatively low value; and, substantially irrespective of the copper content of the aluminum alloy matrix metal, when the magnesium content was either at the lower value of approximately 0% or at the higher value of approximately 4%, the bending strength of the composite material test sample pieces had a relatively low value. Further, it will be seen that, when the magnesium content was in the range of from approximately 2% to approximately 3%, the bending strength of the composite material test sample pieces attained a substantially maximum value; and, when the magnesium content increased above or decreased below this range, then the boiling strength of the composite material test sanmple pieces decreased gradually; while, when the magnesium content was either in the low range below approximately 0.5% or was in the high range above approximately 3.5%, the bending strength of the composite material test sample pieces reduced relatively suddenly with decrease (excluding the cases where the copper content of the matrix metal was approximately 6% or approximately 6.5%) or increase respectively of the magnesium content; and, when the magnesium content was approximately 4%, the bending strength of the composite material test sample pieces had substantially the same value as, or at least not a greater value than, when the magnesium content was approximately 0%.

From the results of these bending strength tests will be seen that, in order to provide for a good and appropriate bending strength for a composite material having as reinforcing fiber material such crystalline alumina-silica short fibers with Al₂ O₃ content approximately 35% in volume proportions of approximately 30% and approximately 10% and having as matrix metal an Al-Cu-Mg type aluminum alloy, with remainder substantially Al₂ O₃, it is preferable that the copper content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 2% to approximately 6%, while the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 0.5% to approximately 3.5%.

THE FIFTH SET OF PREFERRED EMBODIMENTS

For the fifth set of preferred embodiments of the present invention, again a different type of reinforcing fiber was chosen. The present inventors manufactured by using the high pressure casting method samples of various composite materials, utilizing as matrix metal Al-Cu-Mg type aluminum alloys of various compositions, and utilizing as reinforcing material amorphous alumina-silica short fiber material, which in this case had composition about 49% Al₂ O₃ and remainder substantially SiO₂, and which again had average fiber length about 1 mm and average fiber diameter about 3 microns. Then the present inventors conducted evaluations of the bending strength of the various resulting composite material sample pieces.

First, a set of fifty six quantities of aluminum alloy material the same as those utilized in the previously described sets of preferred embodiments were produced in the same manner as before, again having as base material aluminum and having various quantities of magnesium and copper mixed therewith. And an appropriate number (now a hundred and sixty eight) of amorphous alumina-silica short type fiber material preforms were as before made by the method disclosed above with respect to the previously described sets of preferred embodiments, one set of said amorphous alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 20%, a second set of said amorphous alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 10%, and a third set of said amorphous alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 5%, by contrast to the various sets of preferred embodiments described above. These preforms had substantially the same dimensions as the preforms of the previously described sets of preferred embodiments.

Next, substantially as before, each of these amorphous alumina-silica short fiber type material preforms was subjected to high pressure casting together with an appropriate quantity of one of the aluminum alloys A1 through A56 described above, utilizing operational parameters substantially as before. The solidified aluminum alloy mass with the preform included therein was then removed from the casting mold, and the peripheral portion of said solidified aluminum alloy mass and the stainless steel case were machined away, leaving only a sample piece of composite material which had amorphous alumina-silica short type fiber material as reinforcing material and the appropriate one of the aluminum alloys A1 through A56 as matrix metal. The volume proportion of amorphous alumina-silica short type fibers in each of the first set of the resulting composite material sample pieces was thus now approximately 20%, in each of the second set of the resulting composite material sample pieces was thus now approximately 10%, and in each of the third set of the resulting composite material sample pieces was thus now approximately 5%. And post processing steps were performed on the composite material samples, substantially as before. From each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there was cut a bending strength test piece of dimensions and parameters substantially as in the case of the previously described sets of preferred embodiments, and for each of these composite material bending strength test pieces a bending strength test was carried out, again substantially as before.

The results of these bending strength tests were as shown in Table 5 and as summarized in the graphs of FIGS. 10 through 12, which relate to the cases of fiber volume proportion being equal to 20%, 10%, and 5% respectively; thus, FIGS. 10 through 12 correspond to FIGS. 1 through 3 relating to the first set of preferred embodiments, to FIGS. 4 and 5 relating to the second set of preferred embodiments, to FIGS. 6 and 7 relating to the third preferred embodiment set, and to FIGS. 8 and 9 relating to the fourth preferred embodiment set. In the graphs of FIGS. 10 through 12, there are again shown relations between magnesium content and the bending strength (in kg/mm²) of certain of the composite material test pieces, for percentage contents of copper fixed along the various lines thereof.

From Table 5 and from FIGS. 10 through 12 it will be understood that for all of these composite materials, when as in these cases the volume proportion of the reinforcing amorphous alumina-silica short fiber material of these bending strength composite material test sample pieces was approximately 20%, was approximately 10%, or was approximately 5%, substantially irrespective of the magnesium content of the aluminum alloy matrix metal, when the copper content was either at the low extreme of approximately 1.5% or was at the high extreme of approximately 6.5%, the bending strength of the composite material test sample pieces had a relatively low value; and, substantially irrespective of the copper content of the aluminum alloy matrix metal, when the magnesium content was either at the lower value of approximately 0% or at the higher value of approximately 4%, the bending strength of the composite material test sample pieces had a relatively low value. Further, it will be seen that, when the magnesium content was in the range of from approximately 1% to approximately 2%, the bending strength of the composite material test sample pieces attained a substantially maximum value; and, when the magnesium content increased above or decreased below this range, then the bending strength of the composite material test sample pieces decreased gradually; while, when the magnesium content was either in the low range below approximately 0.5% or was in the high range above approximately 3.5%, the bending strength of the composite material test sample pieces reduced relatively suddenly with decrease (excluding the cases where the copper content of the matrix metal was approximately 6% or approximately 6.5%) or increase respectively of the magnesium content; and, when the magnesium content was approximately 4%, the bending strength of the composite material test sample pieces had substantially the same value as, or at least not a greater value than, when the magnesium content was approximately 0%.

From the results of these bending strength tests it will be seen that,in order to provide for a good and appropriate bending strength for a composite material having as reinforcing fiber material such amorphous alumina-silica short fibers with Al₂ O₃ content approximately 49% in volume proportions of approximately 20%, approximately 10%, and approximately 5% and having as matrix metal an Al-Cu-Mg type aluminum alloy, with remainder substantially Al₂ O₃, it is preferable that the copper content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 2% to approximately 6%, while the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 0.5% to approximately 3.5%, and particularly should be in the range of from approximately 0.5% to approximately 3%.

THE SIXTH SET OF PREFERRED EMBODIMENTS

For the sixth set of preferred embodiments of the present invention, the same type of reinforcing fiber as in the fifth preferred embodiment set, but utilizing different fiber volume proportions, was chosen. The present inventors manufactured by using the high pressure casting method samples of various composite materials, utilizing as matrix metal Al-Cu-Mg type aluminum alloys of various compositions, and utilizing as reinforcing material amorphous alumina-silica short fiber material, which again in this case had compostion about 49% Al₂ O₃ and remainder substantially SiO₂, and which again had average fiber length about 1 mm and average fiber diameter about 3 microns. Then the present inventors conducted evaluations of the bending strength of the various resulting composite material sample pieces.

First, a set of fifty six quantities of aluminum alloy material the same as those utilized in the previously described sets of preferred embodiments were produced in the same manner as before, again having as base material aluminum and having various quantities of magnesium and copper mixed therewith. And an appropriate number (now a hundred and twelve) of amorphous alumina-silica short type fiber material preforms were as before made by the method disclosed above with respect to the previously described sets of preferred embodiments, one set of said amorphous alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 40%, and another set of said amorphous alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 30%, by contrast to the various sets of preferred embodiments described above. These preforms had substantially the same dimensions as the preforms of the previously described sets of preferred embodiments.

Next, substantially as before, each of these amorphous alumina-silica short fiber type material preforms was subjected to high pressure casting together with an appropriate quantity of one of the aluminum alloys A1 through A56 described above, utilizing operational parameters substantially as before. The solidified aluminum alloy mass with the preform included therein was then removed from the casting mold, and the peripheral portion of said solidified aluminum alloy mass and the stainless steel case were machined away, leaving only a sample piece of composite material which had amorphous alumina-silica short type fiber material as reinforcing material and the appropriate one of the aluminum alloys A1 through A56 as matrix metal. The volume proportion of amorphous alumina-silica short type fibers in each of the first set of the resulting composite material sample pieces was thus now approximately 40%, and in each of the second set of the resulting composite material sample pieces was thus now approximately 30%. And post processing steps were performed on the composite material samples, substantially as before. From each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there was cut a bending strength test piece of dimensions and parameters substantially as in the case of the previously described sets of preferred embodiments, and for each of these composite material bending strength test pieces a bending strength test was carried out, again substantially as before.

The results of these bending strength tests were as shown in Table 6 and as summarized in the graphs of FIGS. 13 and 14, which relate to the cases of fiber volume proportion being equal to 40% and 30% respectively; thus, FIGS. 13 and 14 correspond to FIGS. 1 through 3 relating to the first set of preferred embodiments, to FIGS. 4 and 5 relating to the second set of preferred embodiments, to FIGS. 6 and 7 relating to the third preferred embodiment set, to FIGS. 8 and 9 relating to the fourth preferred embodiment set, and to FIGS. 10 through 12 relating to the fifth preferred embodiment set. In the graphs of FIGS. 13 and 14, there are again shown relations between magnesium content and the bending strength (in kg/mm²) of certain of the composite material test pieces, for percentage contents of copper fixed along the various lines thereof.

From Table 6 and from FIGS. 13 and 14 it will be understood that for all of these composite materials, when as in these cases the volume proportion of the reinforcing amorphous alumina-silica short fiber material of these bending strength composite material test sample pieces was approximately 40% or was approximately 30%, substantially irrespective of the magnesium content of the aluminum alloy matrix metal, when the copper content was either at the low extreme of approximately 1.5% or was at the high extreme of approximately 6.5%, the bending strength of the composite material test sample pieces had a relatively low value; and, substantially irrespective of the copper content of the aluminum alloy matrix metal, when the magnesium content was either at the lower value of approximattely 0% or at the higher value of approximately 4%, the bending strength of the composite material test sample pieces had a relatively low value. Further, it will be seen that, when the magnesium content was in the range of from approximately 1% to approximately 2%, the bending strength of the composite material test sample pieces attained a substantially maximum value; and, when the magnesium content increased above or decreased below this range, then the bending strength of the composite material test sample pieces decreased gradually; while, when the magnesium content was either in the low range below approximately 0.5% or was in the high range above approximately 3.5%, the bending strength of the composite material test sample pieces reduced relatively suddenly with decrease or increase respectively of the magnesium content; and, when the magnesium content was approximately 4%, the bending strength of the composite material test sample pieces had substantially the same value as, or at least not a greater value than, when the magnesium content was approximately 0%.

From the results of these bending strength tests it will be seen that, in order to provide for a good and appropriate bending strength for a composite material having as reinforcing fiber material such amorphous alumina-silica short fibers with Al₂ O₃ content approximately 49% in volume proportions of approximately 40% and approximately 30% and having as matrix metal an Al-Cu-Mg type aluminum alloy, with remainder substantially Al₂ O₃, it is preferable that the copper content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 2% to approximately 6% and particularly should be in the range of from approximately 2% to approximately 5.5%, while the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 0.5% to approximately 3.5% and particularly should be in the range of from approximately 0.5% to approximately 3%.

THE SEVENTH SET OF PREFERRED EMBODIMENTS Variation of fiber volume proportion

Since from the above described first through sixth sets of preferred embodiments the fact has been amply established and demonstrated, both in the case that the reinforcing alumina-silica short fibers are crystalline and in the case that said reinforcing alumina-silica short fibers are amorphous, that it is preferable for the copper content of the Al-Cu-Mg type aluminum alloy matrix metal to be in the range of from approximately 2% to approximately 6%, and that it is preferable for the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal to be in the range of from approximately 0.5% to approximately 3.5%, it next was deemed germane to provide a set of tests to establish what fiber volume proportion of the reinforcing alumina-silica type short fibers is most appropriate. This was done, in the seventh set of preferred embodiments now to be described, by varying said fiber volume proportion of the reinforcing alumina-silica type short fiber material while using an Al-Cu-Mg type aluminum alloy matrix metal which had the proportions of copper and magnesium which had as described above been established as being quite good, i.e. which had copper content of approximately 4% and also magnesium content of approximately 1% and remainder substantially aluminum. In other words, an appropriate number (in fact six in each case) of performs made of the crystalline type alumina-silica short fiber material used in the third set of preferred embodiments detailed above, and of the amorphous type alumina-silica short fiber material used in the fifth set of preferred embodiments detailed above, hereinafter denoted respectively as B1 through B6 and C1 through C6, were made by subjecting quantities of the relevant short fiber material to compression forming without using any binder in the same manner as in the above described six sets of preferred embodiments, the six ones in each said set of said alumina-silica type short fiber material performs having fiber volume proportions of approximately 5%, 10%, 20%, 30%, 40%, and 50%. These preforms had substantially the same dimensions and the same type of two dimensional random fiber orientation as the preforms of the six above described sets of preferred embodiments. And, substantially as before, each of these alumina-silica type short fiber material preforms was subjected to high pressure casting together with an appropriate quantity of the aluminum alloy matrix metal described above, utilizing operational parameters substantially as before. In each case, the solidified aluminum alloy mass with the preform included therein was then removed from the casting mold, and as before the peripheral portion of said solidified aluminum alloy mass was machined away along with the stainless steel case which was utilized, leaving only a sample piece of composite material which had alumina-silica type short fiber material as reinforcing material in the appropriate fiber volume proportion and the described aluminum alloy as matrix metal. And post processing and artificial aging processing steps were performed on the composite material samples, similarly to what was done before. From each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there was then cut a bending strength test piece, each of dimensions substantially as in the case of the above described sets of preferred embodiments, and for each of these composite material bending strength test pieces a bending strength test was carried out, again substantially as before. Also, for reference purposes, a similar test sample was cut from a piece of a cast aluminum alloy material which included no reinforcing fiber material at all, said aluminum alloy material having copper content of about 4%, magnesium content of about 1%, and balance substantially aluminum, and having been subjected to post processing and artificial aging processing steps, similarly to what was done before. And for this comparison sample, referred to as A0, a bending strength test was carried out, again substantially as before. The results of these bending strength tests were as shown in the two graphs of FIG. 15, respectively for the crystalline type alumina-silica short reinforcing fiber material samples B1 through B6 and the amorphous alumina-silica type reinforcing fiber material samples C1 through C6; the zero point of each said graph corresponds to the test sample A0 with no reinforcing alumina-silica fiber material at all. Each of these graphs shows the relation between the volume proportion of the alumina-silica type short reinforcing fibers and the bending strength (in kg/mm²) of the composite material test pieces, for the appropriate type of reinforcing fibers.

From FIG. 15, it will be understood that, substantially irrespective of the type of reinforcing alumina-silica short fiber material utilized: when the volume proportion of the alumina-silica type short reinforcing fibers was in the range of up to and including approximately 5% the bending strength of the composite material hardly increased along with an increase in the fiber volume proportion, and its value was close to the bending strength of the aluminum alloy matrix metal by itself with no reinforcing fiber material admixture therewith; when the volume proportion of the alumina-silica type short reinforcing fibers was in the range of 5% to 30% the bending strength of the composite material increased substantially linearly with increase in the fiber volume proportion; and, when the volume proportion of the alumina-silica type short reinforcing fibers increased above 40%, and particularly when said volume proportion of said alumina-silica type short reinforcing fibers increased above 50%, the bending strength of the composite material did not increase very much even with further increase in the fiber volume proportion. From these results described above, it is seen that in a composite material having alumina-silica type short fiber reinforcing material and having as matrix metal an Al-Cu-Mg type aluminum alloy, said Al-Cu-Mg type aluminum alloy matrix metal having a copper content in the range of from approximately 1.5% to approximately 6%, a magnesium content in the range of from approximately 0.5% to approximately 2%, and remainder substantially aluminum, irrespective of the actual type of the reinforcing alumina-silica fibers utilized, it is preferable that the fiber volume proportion of said alumina-silica type short fiber reinforcing material should be in the range of from approximately 5% to approximately 50%, and more preferably should be in the range of from approximately 5% to approximately 40%.

THE EIGHTH SET OF PREFERRED EMBODIMENTS Variation of mullite crystalline proportion

In the particular case that crystalline alumina-silica short fiber material is used as the alumina-silica type short fiber material for reinforcement, in order to assess what value of the mullite crystalline amount of the crystalline alumina-silica short fiber material yields a high value for the bending strength of the composite material, a number of samples of crystalline alumina-silica type short fiber material were formed in a per se known way, a first set of four thereof having proportions of Al₂ O₃ being approximately 65% and balance SiO₂ and including samples with mullite crystalline amounts of 0%, 20%, 40%, and 60%, a second set of four thereof having proportions of Al₂ O₃ being approximately 49% and balance SiO₂ and likewise including samples with mullite crystalline amounts of 0%, 20%, 40%, and 60%, and a third set of four thereof having proportions of Al₂ O₃ being approximately 35% and balance SiO₂ and including samples with mullite crystalline amounts of 0%, 20 %, 40%, and, in this case, only 45%. Then, from each of these twelve crystalline alumina-silica type short fiber material samples, two preforms, one with a fiber volume proportion of approximately 10% and one with a fiber volume proportion of approximately 30%, were formed in the same manner and under the same conditions as in the seven sets of preferred embodiments detailed above. Herein, the 10% fiber volume proportion preforms formed from the four crystalline alumina-silica type short fiber material samples included in the first set thereof having approximately 65% proportion of Al₂ O₃ and mullite crystalline amounts of 0%, 20%, 40%, and 60% will be designated as D0 through D3; the 30% fiber volume proportion preforms formed from said four crystalline alumina-silica type short fiber material samples included in said first set thereof having approximately 65% proportion of Al₂ O₃ and mullite crystalline amounts of 0%, 20%, 40%, and 60% will be designated as E0 through E3; the 10% fiber volume proportion preforms formed from the four crystalline alumina-silica type short fiber material samples included in the second set thereof having approximately 49% proportion of Al₂ O₃ and mullite crystalline amounts of 0%, 20%, 40%, and 60% will be designated as F0 through F3; the 30% fiber volume proportion preforms formed from said four crystalline alumina-silica type short fiber material samples included in said second set thereof having approximately 49% proportion of Al₂ O₃ and mullite crystalline amounts of 0%, 20%, 40%, and 60% will be designated as G0 through G3; the 10% fiber volume proportion preforms formed from the four crystalline alumina-silica type short fiber material samples included in the third set thereof having approximately 35% proportion of Al₂ O₃ and mullite crystalline amounts of 0%, 20%, 40%, and 45% will be designated as H0 through H3; and the 30% fiber volume proportion preforms formed from said four crystalline alumina-silica type short fiber material samples included in said third set thereof having approximately 35% proportion of Al₂ O₃ and mullite crystalline amounts of 0%, 20%, 40%, and 45% will be designated as I0 through I3. Then, using as matrix metal each such preform as a reinforcing fiber mass and an aluminum alloy of which the copper content was approximately 4%, the magnesium content was approximately 2%, and the remainder was substantially aluminum, various composite material sample pieces were manufactured in the same manner and under the same conditions as in the seven sets of preferred embodiments detailed above, the various resulting composite material sample pieces were subjected to liquidizing processing and artificial aging processing in the same manner and under the same conditions as in the various sets of preferred embodiments detailed above, from each composite material sample piece a bending test piece was cut in the same manner and under the same conditions as in the various sets of preferred embodiments detailed above, and for each bending test piece a bending test was carried out, as before. The results of these bending tests are shown in FIG. 16. It should be noted that in FIG. 16 the mullite crystalline amount (in percent) of the crystalline alumina-silica short fiber material which was the reinforcing fiber material is shown along the horizontal axis, while the bending strength of the composite material test pieces is shown along the vertical axis.

From FIG. 16 it will be seen that, in the case that such an aluminum alloy as detailed above is utilized as the matrix metal, even when the mullite crystalline amount included in the reinforcing fibers is relatively low, the bending strength of the resulting composite material has a relatively high value, and, whatever be the variation in the mullite crystalline amount included in the reinforcing fibers, the variation in the bending strength of the resulting composite material is relatively low. Therefore it will be seen that, in the case that crystalline alumina-silica short fiber material is used as the alumina-silica short fiber material for reinforcing the material of the present invention, it is acceptable for the value of the mullite crystalline amount therein to be more or less any value.

THE SECOND GROUPING OF PREFERRED EMBODIMENT SETS

For the second grouping of sets of preferred embodiments of the present invention, reinforcing fibers similar to those utilized in the preferred embodiment sets of the first grouping described above, but including substantially higher proportions of Al₂ O₃, were chosen.

THE NINTH SET OF PREFERRED EMBODIMENTS

For the ninth set of preferred embodiments of the present invention, the present inventors manufactured by using the high pressure casting method samples of various composite materials, utilizing as matrix metal Al-Cu-Mg type aluminum alloys of various compositions, and utilizing as reinforcing material crystalline alumina-silica short fiber material, which now in this case had composition about 72% Al₂ O₃ and remainder substantially SiO₂, and had a content of the mullite crystalline form of approximately 60%, and which again had average fiber length about 1 mm and average fiber diameter about 3 microns. Then the present inventors conducted evaluations of the bending strength of the various resulting composite material sample pieces.

First, a set of fifty six quantities of aluminum alloy material the same as those utilized in the previously described sets of preferred embodiments were produced in the same manner as before, again having as base material aluminum and having various quantities of magnesium and copper mixed therewith. And an appropriate number (now a hundred and fifty six) of crystalline alumina-silica short type fiber material preforms were as before made by the method disclosed above with respect to the previously described sets of preferred embodiments, one set of said crystalline alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 20%, another set of said crystalline alumina-silica short type fiber material preforms having a fiber volume proportion of approximately 10%, and another set of said crystalline alumina-silica short type fiber material preforms having a fiber volume proportion of approximately 5%. These preforms had substantially the same dimensions as the preforms of the previously described sets of preferred embodiments.

Next, substantially as before, each of these crystalline alumina-silica short fiber type material preforms was subjected to high pressure casting together with an appropriate quantity of one of the aluminum alloys A1 through A56 described above, utilizing operational parameters substantially as before. The solidified aluminum alloy mass with the preform included therein was then removed from the casting mold, and the peripheral portion of said solidified aluminum alloy mass and the stainless steel case were machined away, leaving only a sample piece of composite material which had crystalline alumina-silica short type fiber material as reinforcing material and the appropriate one of the aluminum alloys A1 through A56 as matrix metal. The volume proportion of crystalline alumina-silica type fibers in each of the first set of the resulting composite material sample pieces was thus now approximately 20%, in each of the second set of the resulting composite material sample pieces was thus now approximately 10%, and in each of the third set of the resulting composite material sample pieces was thus now approximately 5%. And post processing steps were preformed on the composite material samples, substantially as before. From each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there was cut a bending strength test piece of dimensions and parameters substantially as in the case of the previously described sets of preferred embodiments, and for each of these composite material bending strength test pieces a bending strength test was carried out, again substantially as before.

The results of these bending strength tests were as shown in the first three column of Table 6 and as summarized in the graphs of FIGS. 20 through 22, which relate to the cases of fiber volume proportion being equal to 20%, 10%, and 5% respectively; thus, FIGS. 20 through 22 correspond to FIGS. 1 through 3 relating to the first set of preferred embodiments, to FIGS. 4 and 5 relating to the second set of preferred embodiments, to FIGS. 6 and 7 relating to the third preferred embodiment set, to FIGS. 8 and 9 relating to the fourth preferred embodiment set, to FIGS. 10 through 12 relating to the fifth preferred embodiment set, and to FIGS. 13 and 14 relating to te sixth preferred embodiment set. In the graphs of FIGS. 20 through 22, there are again shown relations between magnesium content and the bending strength (in kg/mm²) of certain of the composite material test pieces, for percentage contents of copper fixed along the various lines thereof.

From Table 6 and from FIGS. 20 through 22 it will be understood that for all of these composite materials, when as in these cases the volume proportion of the reinforcing crystalline alumina-silica short fiber material of these bending strength composite material test sample pieces was approximately 20%, was approximately 10%, or was approximately 5%, substantially irrespective of the magnesium content of the aluminum alloy matrix metal, when the copper content was either at the low extreme of approximately 1.5% or was at the high extreme of approximately 6.5%, the bending strength of the composite material test sample pieces had a relatively low value; and, substantially irrespective of the copper content of the aluminum alloy matrix metal, when the magnesium content was either at the lower value of approximately 0% or at the higher value of approximately 4%, the bending strength of the composite material test sample pieces had a relatively low value. Further, it will be seen that, when the magnesium content was in the range of from approximately 2% to approximately 3%, the bending strength of the composite material test sample pieces attained a substantially maximum value; and, when the magnesium content increased above or decreased below this range, then the bending strength of the composite material test sample pieces decreased gradually; while, when the magnesium content was in the high range above approximately 3.5%, the bending strength of the composite material test sample pieces reduced relatively suddenly with increase of the magnesium content; and, when the magnesium content was approximately 4%, the bending strength of the composite material test sample pieces had substantially the same value as when the magnesium content was approximately 0%.

From the results of these bending strength tests it will be seen that, in order to provide for a good and appropriate bending strength for a composite material having as reinforcing fiber material such crystalline alumina-silica short fibers with Al₂ O₃ content approximately 72% in volume proportions of approximately 20%, approximately 10%, and approximately 5% and having as matrix metal an Al-Cu-Mg type aluminum alloy, with remainder substantially Al₂ O₃, it is preferable that the copper content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 2% to approximately 6%, while the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 0.5% to approximately 3.5% and particularly should be in the range of from approximately 1.5% to approximately 3.5%.

THE TENTH SET OF PREFERRED EMBODIMENTS

For the tenth set of preferred embodiments of the present invention, the present inventors manufactured by using the high pressure casting method samples of various composite materials, utilizing as matrix metal Al-Cu-Mg type aluminum alloys of various compositions, and utilizing as reinforcing material crystalline alumina-silica short fiber material, which again in this case had composition about 72% Al₂ O₃ and remainder substantially SiO₂, and had a content of the mullite crystalline form of approximately 60%, and which again had average fiber length about 1 mm and average fiber diameter about 3 microns. Then the present inventors conducted evaluations of the bending strength of the various resulting composite material sample pieces.

First, a set of fifty six quantities of aluminum alloy material the same as those utilized in the previously described sets of preferred embodiments were produced in the same manner as before, again having as base material aluminum and having various quantities of magnesium and copper mixed therewith. And an appropriate number (now a hundred and eight) of crystalline alumina-silica short type fiber material preforms were as before made by the method disclosed above with respect to the previously described sets of preferred embodiments, one set of said crystalline alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 40%, and another set of said crystalline alumina-silica short type fiber material preforms having a fiber volume proportion of approximately 30%. These preforms again had substantially the same dimensions as the preforms of the previously described sets of preferred embodiments.

Next, substantially as before, each of these crystalline alumina-silica short fiber type material preforms was subjected to high pressure casting together with an appropriate quantity of one of the aluminum alloys A1 through A56 described above, utilizing operational parameters substantially as before. The solidified aluminum alloy mass with the preform included therein was then removed from the casting mold, and the peripheral portion of said solidified aluminum alloy mass and the stainless steel case were machined away, leaving only a sample piece of composite material which had crystalline alumina-silica short type fiber material as reinforcing material and the appropriate one of the aluminum alloys A1 through A56 as matrix metal. The volume proportion of crystalline alumina-silica short type fibers in each of the first set of the resulting composite material sample pieces was thus now approximately 40%, and in each of the second set of the resulting composite material sample pieces was thus now approximately 30%. And post processing steps were performed on the composite material samples, substantially as before. From each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there was cut a bending strength test piece of dimensions and parameters substantially as in the case of the previously described sets of preferred embodiments, and for each of these composite material bending strength test pieces a bending strength test was carried out, again substantially as before.

The results of these bending strength tests were as shown in the last two columns of Table 6 and as summarized in the graphs of FIGS. 23 and 24, which relate to the cases of fiber volume proportion being equal to 40% and 30% respectively; thus, FIGS. 23 and 24 correspond to FIGS. 1 through 3 relating to the first set of preferred embodiments, to FIGS. 4 and 5 relating to the second set of preferred embodiments, to FIGS. 6 and 7 relating to the third preferred embodiment set, to FIGS. 8 and 9 relating to the fourth preferred embodiment set, to FIGS. 10 through 12 relating to the fifth preferred embodiment set, to FIGS. 13 and 14 relating to the sixth preferred embodiment set, and to FIGS. 20 through 22 relating to the ninth preferred embodiment set. In the graphs of FIGS. 23 and 24, there are again shown relations between magnesium content and the bending strength (in kg/mm²) of certain of the composite material test pieces, for percentage contents of copper fixed along the various lines thereof.

From Table 6 and from FIGS. 23 and 24 it will be understood that for all of these composite materials, when as in these cases the volume proportion of the reinforcing crystalline alumina-silica short fiber material of these bending strength composite material test sample pieces was approximately 40% or was approximately 30%, substantially irrespective of the magnesium content of the aluminum alloy matrix metal, when the copper content was either at the low extreme of approximately 1.5% or was at the high extreme of approximately 6.5%, the bending strength of the composite material test sample pieces had a relatively low value; and, substantially irrespective of the copper content of the aluminum alloy matrix metal, when the magnesium content was either at the lower value of approximately 0% or at the higher value of approximately 4%, the bending strength of the composite material test sample pieces had a relatively low value. Further, it will be seen that, when the magnesium content was in the range of from approximately 2% to approximately 3%, the bending strength of the composite material test sample pieces attained a substantially maximum value; and, when the magnesium content increased above or decreased below this range, then the bending strength of the composite material test sample pieces decreased gradually; while, when the magnesium content was in the high range above approximately 3.5%, the bending strength of the composite material test sample pieces reduced relatively suddenly with increase of the magnesium content; and, when the magnesium content was approximately 4%, the bending strength of the composite material test sample pieces had substantially the same value as when the magnesium content was approximately 0%.

From the results of these bending strength tests it will be seen that, in order to provide for a good and appropriate bending strength for a composite material having as reinforcing fiber material such crystalline alumina-silica short fibers with Al₂ O₃ content approximately 72% in volume proportions of approximately 40% and approximately 30% and having as matrix metal an Al-Cu-Mg type aluminum alloy, with remainder substantially Al₂ O₃, it is preferable that the copper content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 2% to approximately 6% and particularly should be in the range of from approximately 2% to approximately 5.5%, while the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 0.5% to approximately 3.5% and particularly should be in the range of from approximately 1.5% to approximately 3.5%.

THE ELEVENTH SET OF PREFERRED EMBODIMENTS

For the eleventh set of preferred embodiments of the present invention, the present inventors manufactured by using the high pressure casting method samples of various composite materials, utilizing as matrix metal Al-Cu-Mg type aluminum alloys of various compositions, and utilizing as reinforcing material, now, amorphous alumina-silica short fiber material, which again in this case had composition about 72% Al₂ O₃ and remainder substantially SiO₂, and which now had average fiber length about 2 mm while still having average fiber diameter about 3 microns. Then the present inventors conducted evaluations of the bending strength of the various resulting composite material sample pieces.

First, a set of fifty six quantities of aluminum alloy material the same as those utilized in the previously described sets of preferred embodiments were produced in the same manner as before, again having as base material aluminum and having various quantities of magnesium and copper mixed therewith. And an appropriate number (now fifty six) of amorphous alumina-silica short type fiber material preforms were as before made by the method disclosed above with respect to the peviously described sets of preferred embodiments, said set of said amorphous alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 10%. These preforms again had substantially the same dimensions as the preforms of the previously described sets of preferred embodiments.

Next, substantially as before, each of these amorphous alumina-silica short fiber type material preforms was subjected to high pressure casting together with an appropriate quantity of one of the aluminum alloys A1 through A56 described above, utilizing operational parameters substantially as before. The solidified aluminum alloy mass with the preform included therein was then removed from the casting mold, and the peripheral portion of said solidified aluminum alloy mass and the stainless steel case were machined away, leaving only a sample piece of composite material which had amorphous alumina-silica short type fiber material as reinforcing material and the appropriate one of the aluminum alloys A1 through A56 as matrix metal. The volume proportion of amorphous alumina-silica short type fibers in each of this set of the resulting composite material sample pieces was thus now approximately 10%. And post processing steps were preformed on the composite material samples, substantially as before. From each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there were cut a bending strength test piece of dimensions and parameters substantailly as in the case of the previously described sets of preferred embodiments, and for each of these composite material bending strength test pieces a bending strength test was carried out, again substantially as before.

The results of these bending strength tests were as shown in the first column of Table 7 and as summarized in the graphs of FIG. 25; thus, FIG. 25 corresponds to FIGS. 1 through 3 relating to the first set of preferred embodiments, to FIGS. 4 through 5 relating to the second set of preferred embodiments, to FIGS. 6 and 7 relating to the third preferred embodiment set, to FIGS. 8 and 9 relating to the fourth preferred embodiment set, to FIGS. 10 through 12 relating to the fifth preferred embodiment set, to FIGS. 13 and 14 relating to the sixth preferred embodiment set, to FIGS. 20 through 22 relating to the ninth preferred embodiment set, and to FIGS. 23 and 24 relating to the tenth preferred embodiment set. In the graphs of FIG. 25, there are again shown relations between magnesium content and the bending strength (in kg/mm²) of certain of the composite material test pieces, for percentage contents of copper fixed along the various lines thereof.

From Table 7 and from FIG. 25 it will be understood that for all of these composite materials, when as in these cases the volume proportion of the reinforcing amorphous alumina-silica short fiber material of these bending strength composite material test sample pieces was approximately 10%, substantially irrespective of the magnesium content of the aluminum alloy matrix metal, when the copper content was either at the low extreme of approximately 1.5% or was at the high extreme of approximately 6.5%, the bending strength of the composite material test sample pieces had a relatively low value; and, substantially irrespective of the copper content of the aluminum alloy matrix metal, when the magnesium content was either at the lower value of approximately 0% or at the higher value of approximately 4%, the bending strength of the composite material test sample pieces had a relatively low value. Further, it will be seen that, when the magnesium content was in the range of from approximately 2% to approximately 3%, the bending strength of the composite material test sample pieces attained a substantially maximum value; and, when the magnesium content increased above or decreased below this range, then the bending strength of the composite material test sample pieces decreased gradually; while, particularly, when the magnesium content was in the high range above approximately 3.5%, the bending strength of the composite material test sample pieces reduced relatively suddenly with increase of the magnesium content; and, when the magnesium content was approximately 4%, the bending strength of the composite material test sample pieces had a substantially lower value than when the magnesium content was approximately 0%.

From the results of these bending strength tests it will be seen that, in order to provide for a good and appropriate bending strength for a composite material having as reinforcing fiber material such amorphous alumina-silica short fibers with Al₂ O₃ content approximately 72% in volume proportion of approximately 10% and having as matrix metal an Al-Cu-Mg type aluminum alloy, with remainder substantially Al₂ O₃, it is preferable that the copper content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 2% to approximately 6%, while the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 0.5% to approximately 3.5% and particularly should be in the range of from approximately 1.5% to approximately 3.5%.

THE TWELFTH SET OF PREFERRED EMBODIMENTS

For the twelfth set of preferred embodiments of the present invention, the present inventors manufactured by using the high pressure casting method samples of various composite materials, utilizing as matrix metal Al-Cu-Mg type aluminum alloys of various compositions, and again utilizing as reinforcing material amorphous alumina-silica short fiber material, which again in this case had composition about 72% Al₂ O₃ and remainder substantially SiO₂, and which now had average fiber length about 0.8 mm while still having average fiber diameter about 3 microns. Then the present inventors conducted evaluations of the bending strength of the various resulting composite material sample pieces.

First, a set of fifty six quantities of aluminum alloy material the same as those utilized in the previously described sets of preferred embodiments were produced in the same manner as before, again having as base material aluminum and having various quantities of magnesium and copper mixed therewith. And an appropriate number (again fifty six) of amorphous alumina-silica short type fiber material preforms were as before made by the method disclosed above with respect to the previously described sets of preferred embodiments, said set of said amorphous alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 30%. These preforms again had substantially the same dimensions as the preforms of the previously described sets of preferred embodiments.

Next, substantially as before, each of these amorphous alumina-silica short fiber type material preforms was subjected to high pressure casting together with an appropriate quantity of one of the aluminum alloys A1 through A56 described above, utilizing operational parameters substantially as before. The solidified aluminum alloy mass with the preform included therein was then removed from the casting mold, and the peripheral portion of said solidified aluminum alloy mass and the stainless steel case were machined away, leaving only a sample piece of composite material which had amorphous alumina-silica short type fiber material as reinforcing material and the appropriate one of the aluminum alloys A1 through A56 as matrix metal. The volume proportion of amorphous alumina-silica short type fibers in each of this set of the resulting composite material sample pieces was thus now approximately 30%. And post processing steps were performed on the composite material samples, substantially as before. From each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there was cut a bending strength test piece of dimensions and parameters substantially as in the case of the previously described sets of preferred embodiments, and for each of these composite material bending strength test pieces a bending strength test was carried out, again substantially as before.

The results of these bending strength tests were as shown in the last column of Table 7 and as summarized in the graphs of FIG. 26; thus, FIG. 26 corresponds to FIGS. 1 through 3 relating to the first set of preferred embodiments, to FIGS. 4 and 5 relating to the second set of preferred embodiments, to FIGS. 6 and 7 relating to the third preferred embodiment set, to FIGS. 8 and 9 relating to the fourth preferred embodiment set, to FIGS. 10 through 12 relating to the fifth preferred embodiment set, to FIGS. 13 and 14 relating to the sixth preferred embodiment set, to FIGS. 20 through 22 relating to the ninth preferred embodiment set, to FIGS. 23 and 24 relating to the tenth preferred embodiment set, and to FIG. 25 relating to the eleventh preferred embodiment set. In the graphs of FIG. 26, there are again shown relations between magnesium content and the bending strength (in kg/mm²) of certain of the composite material test pieces, for percentage contents of copper fixed along the various lines thereof. From Table 7 and from FIG. 26 it will be understood that for all of these composite materials, when as in these cases the volume proportion of the reinforcing amorphous alumina-silica short fiber material of these bending strength composite material test sample pieces was approximately 30%, substantially irrespective of the magnesium content of the aluminum alloy matrix metal, when the copper content was either at the low extreme of approximately 1.5% or was at the high extreme of approximately 6.5%, the bending strength of the composite material test sample pieces had a relatively low value; and, substantially irrespective of the copper content of the aluminum alloy matrix metal, when the magnesium content was either at the lower value of approximately 0% or at the higher value of approximately 4%, the bending strength of the composite material test sample pieces had a relatively low value. Further, it will be seen that, when the magnesium content was in the range of from approximately 2% to approximately 3%, the bending strength of the composite material test sample pieces attained a substantially maximum value; and, when the magnesium content increased above or decreased below this range, then the bending strength of the composite material test sample pieces decreased gradually; while, particularly, when the magnesium content was in the high range above approximately 3.5%, the bending strength of the composite material test sample pieces reduced relatively suddenly with increase of the magnesium content; and, when the magnesium content was approximately 4%, the bending strength of the composite material test sample pieces had a substantially lower value than when the magnesium content was approximately 0%.

From the results of these bending strength tests it will be seen that, in order to provide for a good and appropriate bending strength for a composite material having as reinforcing fiber material such amorphous alumina-silica short fibers with Al₂ O₃ content approximately 72% in volume proportion of approximately 30% and having as matrix metal an Al-Cu-Mg type aluminum alloy, with remainder substantially Al₂ O₃, it is preferable that the copper content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 2% to approximately 6% and particularly should be in the range of from approximately 2% to approximately 5.5%, while the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 0.5% to approximately 3.5% and particularly should be in the range of from approximately 1.5% to approximately 3.5%.

THE THIRTEENTH SET OF PREFERRED EMBODIMENTS

For the thirteenth set of preferred embodiments of the present invention, the present inventors manufactured by using the high pressure casting method samples of various composite materials, utilizing as matrix metal Al-Cu-Mg type aluminum alloys of various compositions, and now again utilizing as reinforcing material crystalline alumina-silica short fiber material, which now in this case had composition about 77% Al₂ O₃ and remainder substantially SiO₂, with mullite crystalline proportion approximately 60%, and which now had average fiber length about 1.5 mm and also now had average fiber diameter about 3.2 microns. Then the present inventors conducted evaluations of the bending strength of the various resulting composite material sample pieces.

First, a set of fifty six quantities of aluminum alloy material the same as those utilized in the previously described sets of preferred embodiments were produced in the same manner as before, again having as base material aluminum and having various quantities of magnesium and copper mixed therewith. And an appropriate number (again fifty six) of crystalline alumina-silica short type fiber material preforms were as before made by the method disclosed above with respect to the previously described sets of preferred embodiments, said set of said crystalline alumina-silica short type fiber material preforms now having a fiber volume proportion of approximately 10%. These preforms again had substantially the same dimensions as the preforms of the previously described sets of preferred embodiments.

Next, substantially as before, each of these crystalline alumina-silica short fiber type material preforms was subjected to high pressure casting together with an appropriate quantity of one of the aluminum alloys A1 through A56 described above, utilizing operational parameters substantially as before. The solidified aluminum alloy mass with the preform included therein was then removed from the casting mold, and the peripheral portion of said solidified aluminum alloy mass and the stainless steel case were machined away, leaving only a sample piece of composite material which had crystalline alumina-silica short type fiber material as reinforcing material and the appropriate one of the aluminum alloys A1 through A56 as matrix metal. The volume proportion of crystalline alumina-silica short type fibers in each of this set of the resulting composite material sample pieces was thus now approximately 10%. And post processing steps were performed on the composite material samples, substantially as before. From each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there was cut a bending strength test piece of dimensions and parameters substantially as in the case of the previously described sets of preferred embodiments, and for each of these composite material bending strength test pieces a bending strength test was carried out, again substantially as before.

The results of these bending strength tests were as shown in column I of Table 8 and as summarized in the graphs of FIG. 27; thus, FIG. 27 corresponds to FIGS. 1 through 3 relating to the first set of preferred embodiments, to FIGS. 4 and 5 relating to the second set of preferred embodiments, to FIGS. 6 and 7 relating to the third preferred embodiment set, to FIGS. 8 and 9 relating to the fourth preferred embodiment set, to FIGS. 10 through 12 relating to the fifth preferred embodiment set, to FIGS. 13 and 14 relating to the sixth preferred embodiment set, to FIGS. 20 through 22, relating to the ninth preferred embodiment set, to FIGS. 23 and 24 relating to the tenth preferred embodiment set, and to FIGS. 25 and 26 relating to the eleventh and the twelfth preferred embodiment sets respectively. In the graphs of FIG. 27, there are again shown relations between magnesium content and the bending strength (in kg/mm²) of certain of the composite material test pieces, for percentage contents of copper fixed along the various lines thereof.

From Table 8 and from FIG. 27 it will be understood that for all of these composite materials, when as in these cases the volume proportion of the reinforcing crystalline alumina-silica short fiber material of these bending strength composite material test sample pieces was approximately 10%, substantially irrespective of the magnesium content of the aluminum alloy matrix metal, when the copper content was either at the low extreme of approximately 1.5% or was at the high extreme of approximately 6.5%, the bending strength of the composite material test sample pieces had a relatively low value; and, substantially irrespective of the copper content of the aluminum alloy matrix metal, when the magnesium content was either at the lower value of approximately 0% or at the higher value of approximately 4%, the bending strength of the composite material test sample pieces had a relatively low value. Further, it will be seen that, when the magnesium content was in the range of from approximately 2% to approximately 3%, the bending strength of the composite material test sample pieces attained a substantially maximum value; and, when the magnesium content increased above or decreased below this range, then the bending strength of the composite material test sample pieces decreased gradually; while, particularly, when the magnesium content was in the high range above approximately 3.5%, the bending strength of the composite material test sample pieces reduced relatively suddenly with increase of the magnesium content; and, when the magnesium content was approximately 4%, the bending strength of the composite material test sample pieces had a substantially the same or lower value than when the magnesium content was approximately 0%.

From the results of these bending strength tests it will be seen that, in order to provide for a good and appropriate bending strength for a composite material having as reinforcing fiber material such crystalline alumina-silica short fibers with Al₂ O₃ content approximately 77% with mullite crystalline proportion approximately 60% in volume proportion of approximately 10% and having as matrix metal an Al-Cu-Mg type aluminum alloy, with remainder substantially Al₂ O₃, it is preferable that the copper content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 2% to approximately 6%, while the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 0.5% to approximately 3.5% and particularly should be in the range of from approximately 1.5% to approximately 3.5%.

THE FOURTEENTH SET OF PREFERRED EMBODIMENTS

For the fourteenth set of preferred embodiments of the present invention, the present inventors manufactured by using the high pressure casting method samples of various composite materials, utilizing as matrix metal Al-Cu-Mg type aluminum alloys of various compositions, and now again utilizing as reinforcing material amorphous alumina-silica short fiber material, which again in this case had composition about 77% Al₂ O₃ and remainder substantially SiO₂, and which now had average fiber length about 0.6 mm and again had average fiber diameter about 3.2 microns. Then the present inventors conducted evaluations of the bending strength of the various resulting composite material sample pieces.

The results of these bending strength tests were as shown in column II of Table 8 and as summarized in the graphs of FIG. 28; thus, FIG. 28 corresponds to FIGS. 1 through 3 relating to the first set of preferred embodiments, to FIGS. 4 and 5 relating to the second set of preferred embodiments, to FIGS. 6 and 7 relating to the third preferred embodiment set, to FIGS. 8 and 9 relating to the fourth preferred embodiment set, to FIGS. 10 through 12 relating to the fifth preferred embodiment set, to FIGS. 13 and 14 relating to the sixth preferred embodiment set, to FIGS. 20 through 22 relating to the ninth preferred embodiment set, to FIGS. 23 and 24 relating to the tenth preferred embodiment set, and to FIGS. 25 through 27 relating to the eleventh through the thirteenth preferred embodiment sets respectively. In the graphs of FIG. 28, there are again shown relations between magnesium content and the bending strength (in kg/mm²) of certain of the composite material test pieces, for percentage contents of copper fixed along the various lines thereof.

From Table 8 and from FIG. 28 it will be understood that for all of these composite materials, when as in these cases the volume proportion of the reinforcing amorphous alumina-silica short fiber material of these bending strength composite material test sample pieces was approximately 30%, substantially irrespective of the magnesium content of the aluminum alloy matrix metal, when the copper content was either at the low extreme of approximately 1.5% or was at the high extreme of approximately 6.5%, the bending strength of the composite material test sample pieces had a relatively low value; and, substantially irrespective of the copper content of the aluminum alloy matrix metal, when the magnesium content was either at the lower value of approximately 0% or at the higher value of approximately 4%, the bending strength of the composite material test sample pieces had a relatively low value. Further, it will be seen that, when the magnesium content was in the range of from approximately 2% to approximately 3%, the bending strength of the composite material test sample pieces attained a substantially maximum value; and, when the magnesium content increased above or decreased below this range, then the bending strength of the composite material test sample pieces decreased gradually; while, particularly, when the magnesium content was in the high range above approximately 3.5%, the bending strength of the composite material test sample pieces reduced relatively suddenly with increase of the magnesium content; and, when the magnesium content was approximately 4%, the bending strength of the composite material test sample pieces had a substantially lower value than when the magnesium content was approximately 0%.

From the results of these bending strength tests it will be seen that, in order to provide for a good and appropriate bending strength for a composite material having as reinforcing fiber material such amorphous alumina-silica short fibers with Al₂ O₃ content approximately 77% in volume proportion of approximately 30% and having as matrix metal an Al-Cu-Mg type aluminum alloy, with remainder substantially Al₂ O₃, it is preferable that the copper content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 2% to approximately 6% and particularly should be in the range of from approximately 2% to approximately 5.5%, while the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 0.5% to approximately 3.5% and particularly should be in the range of from approximately 1.5% to approximately 3.5%.

THE FIFTEENTH SET OF PREFERRED EMBODIMENTS

For the fifteenth set of preferred embodiments of the present invention, the present inventors manufactured by using the high pressure casting method samples of various composite materials, utilizing as matrix metal Al-Cu-Mg type aluminum alloys of various compositions, and now utilizing as reinforcing material crystalline alumina-silica short fiber material, which again in this case had composition about 67% Al₂ O₃ and remainder substantially SiO₂, and had mullite crystalline proportion of approximately 60%, and which now had average fiber length about 0.3 mm and average fiber diameter about 2.6 microns. Then the present inventors conducted evaluations of the bending strength of the various resulting composite material sample pieces.

First, a set of fifty six quantities of aluminum alloy material the same as those utilized in the previously described sets of preferred embodiments were produced in the same manner as before, again having as base material aluminum and having various quantities of magnesium and copper mixed therewith. And an appropriate number (again fifty six) of crystalline alumina-silica short type fiber material preforms were as before made by the method disclosed above with respect to the previously described sets of preferred embodiments, said set of said crystalline alumina-silica short type fiber material preforms again having a fiber volume proportion of approximately 30%. These preforms again had substantially the same dimensions as the preforms of the previously described sets of preferred embodiments.

Next, substantially as before, each of these crystalline alumina-silica short fiber type material preforms was subjected to high pressure casting together with an appropriate quantity of the aluminum alloy A1 through A56 described above, utilizing operational parameters substantially as before. The solidified aluminum alloy mass with the preform included therein was then removed from the casting mold, and the peripheral portion of said solidified aluminum alloy mass and the stainless steel case were machined away, leaving only a sample piece of composite material which had crystalline alumina-silica short type fiber material as reinforcing material and the appropriate one of the aluminum alloys A1 through A56 as matrix metal. The volume proportion of crystalline alumina-silica short type fibers in each of this set of the resulting composite material sample pieces was thus again approximately 30%. And post processing steps were performed on the composite material samples, substantially as before. From each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there was cut a bending strength test piece of dimensions and parameters substantially as in the case of the previously described sets of preferred embodiments, and for each of these composite material bending strength test pieces a bending strength test was carried out, again substantially as before.

The results of these bending strength tests were as shown in column III of Table 8 and as summarized in the graphs of FIG. 29; thus, FIG. 29 corresponds to FIGS. 1 through 3 relating to the first set of preferred embodiments, to FIGS. 4 and 5 relating to the second set of preferred embodiments, to FIGS. 6 and 7 relating to the third preferred embodiment set, to FIGS. 8 and 9 relating to the fourth preferred embodiment set, to FIGS. 10 through 12 relating to the fifth preferred embodiment set, to FIGS. 13 and 14 relating to the sixth preferred embodiment set, to FIGS. 20 through 22 relating to the ninth preferred embodiment set, to FIGS. 23 and 24 relating to the tenth preferred embodiment set, and to FIGS. 25 through 28 relating to the eleventh through the fourteenth preferred embodiment sets respectively. In the graphs of FIG. 29, there are again shown relations between magnesium content and the bending strength (in kg/mm²) of certain of the composite material test pieces, for percentage contents of copper fixed along the various lines thereof.

From Table 8 and from FIG. 29 it will be understood that for all of these composite materials, when as in these cases the volume proportion of the reinforcing crystalline alumina-silica short fiber material of these bending strength composite material test sample pieces was approximately 30%, substantially irrespective of the magnesium content of the aluminum alloy matrix metal, when the copper content was either at the low extreme of approximately 1.5% or was at the high extreme of approximately 6.5%, the bending strength of the composite material test sample pieces had a relatively low value; and, substantially irrespective of the copper content of the aluminum alloy matrix metal, when the magnesium content was either at the lower value of approximately 0% or at the higher value of approximately 4%, the bending strength of the composite material test sample pieces had a relatively low value. Further, it will be seen that, when the magnesium content was in the range of from approximately 2% to approximately 3%, the bending strength of the composite material test sample pieces attained a substantially maximum value; and, when the magnesium content increased above or decreased below this range, then the bending strength of the composite material test sample pieces decreased gradually; while, particularly, when the magnesium content was in the high range above approximately 3.5%, the bending strength of the composite material test sample pieces reduced relatively suddenly with increase of the magnesium content; and, when the magnesium content was approximately 4%, the bending strength of the composite material test sample pieces had a substantially lower value than when the magnesium content was approximately 0%.

From the results of these bending strength tests it will be seen that, in order to provide for a good and appropriate bending strength for a composite material having as reinforcing fiber material such crystalline alumina-silica short fibers with Al₂ O₃ content approximately 67% and with mullite crystalline proportion approximately 60% in volume proportion of approximately 30% and having as matrix metal an Al-Cu-Mg type aluminum alloy, with remainder substantially Al₂ O₃, it is preferable that the copper content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 2% to approximately 6% and particularly should be in the range of from approximately 2% to approximately 5.5%, while the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 0.5% to approximately 3.5% and particularly should be in the range of from approximately 1.5% to approximately 3.5%.

THE SIXTEENTH SET OF PREFERRED EMBODIMENTS

For the sixteenth set of preferred embodiments of the present invention, the present inventors manufactured by using the high pressure casting method samples of various composite materials, utilizing as matrix metal Al-Cu-Mg type aluminum alloys of various compositions, and now utilizing as reinforcing material amorphous alumina-silica short fiber material, which again in this case had composition about 67% Al₂ O₃ and remainder substantially SiO₂, and which now had average fiber length about 1.2 mm and average fiber diameter about 2.6 microns. Then the present inventors conducted evaluations of the bending strength of the various resulting composite material sample pieces.

First, a set of fifty six quantities of aluminum alloy material the same as those utilized in the previously described sets of preferred embodiments were produced in the same manner as before, again having as base material aluminum and having various quantities of magnesium and copper mixed therewith. And an appropriate number (again fifty six) of amorphous alumina-silica short type fiber material preforms were as before made by the method disclosed above with respect to the previously described sets of preferred embodiments, said set of said amorphous alumina-silica short type fiber material preforms again having a fiber volume proportion of approximately 10%. These preforms again had substantially the same dimensions as the preforms of the previously described sets of preferred embodiments.

Next, substantially as before, each of these amorphous alumina-silica short fiber type material preforms was subjected to high pressure casting together with an appropriate quantity of one of the aluminum alloys A1 through A56 described above, utilizing operational parameters substantially as before. The solidified aluminum alloy mass with the preform included therein was then removed from the casting mold, and the peripheral portion of said solidified aluminum alloy mass and the stainless steel case were machined away, leaving only a sample piece of composite material which had amorphous alumina-silica short type fiber material as reinforcing material and the appropriate one of the aluminum alloys A1 through A56 as matrix metal. The volume proportion of amorphous alumina-silica short type fibers in each of this set of the resulting composite material sample pieces was thus again approximately 10%. And post processing steps were performed on the composite material samples, substantially as before. From each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there was cut a bending strength test piece of dimensions and parameters substantially as in the case of the previously described sets of preferred embodiments, and for each of these composite material bending strength test pieces a bending strength test was carried out, again substantially as before.

The results of these bending strength tests were as shown in column IV of Table 8 and as summarized in the graphs of FIG. 30; thus, FIG. 30 corresponds to FIGS. 1 through 3 relating to the first set of preferred embodiments, to FIGS. 4 and 5 relating to the second set of preferred embodiments, to FIGS. 6 and 7 relating to the third preferred embodiment set, to FIGS. 8 and 9 relating to the fourth preferred embodiment set, to FIGS. 10 through 12 relating to the fifth preferred embodiment set, to FIGS. 13 and 14 relating to the sixth preferred embodiment set, to FIGS. 20 through 22 relating to the ninth preferred embodiment set, to FIGS. 23 and 24 relating to the tenth preferred embodiment set, and to FIGS. 25 through 29 relating to the eleventh through the fifteenth preferred embodiment sets respectively. In the graphs of FIG. 30, there are again shown relations between magnesium content and the bending strength (in kg/mm²) of certain of the composite material test pieces, for percentage contents of copper fixed along the various lines thereof.

From Table 8 and from FIG. 30 it will be understood that for all of these composite materials, when as in these cases the volume proportion of the reinforcing amorphous alumina-silica short fiber material of these bending strength composite material test sample pieces was approximately 10%, substantially irrespective of the magnesium content of the aluminum alloy matrix metal, when the copper content was either at the low extreme of approximately 1.5% or was at the high extreme of approximately 6.5%, the bending strength of the composite material test sample pieces had a relatively low value; and, substantially irrespective of the copper content of the aluminum alloy matrix metal, when the magnesium content was either at the lower value of approximately 0% or at the higher value of approximately 4%, the bending strength of the composite material test sample pieces had a relatively low value. Further, it will be seen that, when the magnesium content was in the range of from approximately 1% to approximately 2%, the bending strength of the composite material test sample pieces attained a substantially maximum value; and, when the magnesium content increased above or decreased below this range, then the bending strength of the composite material test sample pieces decreased gradually; while, particularly, when the magnesium content was in the high range above approximately 3.5%, the bending strength of the composite material test sample pieces reduced relatively suddenly with increase of the magnesium content; and, when the magnesium content was approximately 4%, the bending strength of the composite material test sample pieces had a substantially lower value than when the magnesium content was approximately 0%.

From the results of these bending strength tests it will be seen that, in order to provide for a good and appropriate bending strength for a composite material having as reinforcing fiber material such amorphous alumina-silica short fibers with Al₂ O₃ content approximately 67% in volume proportion of approximately 10% and having as matrix metal an Al-Cu-Mg type aluminum alloy, with remainder substantially Al₂ O₃, it is preferable that the copper content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 2% to approximately 6%, while the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal should be in the range of from approximately 0.5% to approximately 3.5% and particularly should be in the range of from approximately 1.5% to approximately 3.5%.

THE SEVENTEENTH SET OF PREFERRED EMBODIMENTS Variation of fiber volume proportion

Since from the above described ninth through sixteenth sets of preferred embodiments the fact has been amply established and demonstrated, in this case of relatively high Al₂ O₃ proportion, both in the case that the reinforcing alumina-silica short fibers are crystalline and in the case that said reinforcing alumina-silica short fibers are amorphous, that it is preferable for the copper content of the Al-Cu-Mg type aluminum alloy matrix metal to be in the range of from approximately 2% to approximately 6%, and that it is preferable for the magnesium content of said Al-Cu-Mg type aluminum alloy matrix metal to be in the range of from approximately 0.5% to approximately 3.5%, it next was deemed germane to provide a set of tests to establish what fiber volume proportion of the reinforcing alumina-silica type short fibers is most appropriate. This was done, in the seventeenth set of preferred embodiments now to be described, by varying said fiber volume proportion of the reinforcing alumina-silica type short fiber material while using an Al-Cu-Mg type aluminum alloy matrix metal which had proportions of copper and magnesium which had as described above been established as being quite good, i.e. which had copper content of approximately 4% and also magnesium content of approximately 2% and remainder substantially aluminum. In other words, an appropriate number (in fact six in each case) of preforms made of the crystalline type alumina-silica short fiber material used in the ninth set of preferred embodiments detailed above, and of the amorphous type alumina-silica short fiber material used in the thirteenth set of preferred embodiments detailed above, hereinafter denoted respectively as B1 through B6 and C1 through C6, were made by subjecting quantities of the relevant short fiber material to compression forming without using any binder in the same manner as in the above described sets of preferred embodiments, the six ones in each said set of said alumina-silica type short fiber material preforms having fiber volume proportions of approximately 5%, 10%, 20%, 30%, 40%, and 50%. These preforms had substantially the same dimensions and the same type of two dimensional random fiber orientation as the preforms of the above described sets of preferred embodiments. And, substantially as before, each of thes alumina-silica type short fiber material preforms was subjected to high pressure casting together with an appropriate quantity of the aluminum alloy matrix metal described above, utilizing operational parameters substantially as before. In each case, the solidified aluminum alloy mass with the preform included therein was then removed from the casting mold, and as before the peripheral portion of said solidified aluminum alloy mass was machined away along with the stainless steel case which was utilized, leaving only a sample piece of composite material which had one of the described alumina-silica type short fiber material as reinforcing material in the appropriate fiber volume proportion and the described aluminum alloy as matrix metal. And post processing and artificial aging processing steps were performed on the composite material samples, similarly to what was done before. From each of the composite material sample pieces manufactured as described above, to which heat treatment had been applied, there was then cut a bending strength test piece, each of dimensions substantially as in the case of the above described sets of preferred embodiments, and for each of these composite material bending strength test pieces a bending strength test was carried out, again substantially as before. Also, for reference purposes, a similar test sample was cut from a piece of a cast aluminum alloy material which included no reinforcing fiber material at all, said aluminum alloy material having copper content of about 4%, magnesium content of about 2%, and balance substantially aluminum, and having been subjected to post processing and artificial aging processing steps, similarly to what was done before. And for this comparison sample, referred to as A0, a bending strength test was carried out, again substantially as before. The results of these bending strength tests were as shown in the two graphs of FIG. 31, respectively for the crystalline type alumina-silica short reinforcing fiber material samples B1 through B6 and the amorphous alumina-silica type reinforcing fiber material samples C1 through C6; the zero point of each said graph corresponds to the test sample A0 with no reinforcing alumina-silica fiber material at all. Each of these graphs shows the relation between the volume proportion of the alumina-silica type short reinforcing fibers and the bending strength (in kg/mm²) of the composite material test pieces, for the appropriate type of reinforcing fibers.

From FIG. 31, it will be understood that, substantially irrespective of the type of reinforcing alumina-silica short fiber material utilized: when the volume proportion of the alumina-silica type short reinforcing fibers was in the range of up to and including approximately 5% the bending strength of the composite material hardly increased along with an increase in the fiber volume proportion, and its value was close to the bending strength of the aluminum alloy matrix metal by itself with no reinforcing fiber material admixtured therewith; when the volume proportion of the alumina-silica type short reinforcing fibers was in the range of 5% to 30% or was in the range of 5% to 40%, the bending strength of the composite material increased substantially linearly with increase in the fiber volume proportion; and, when the volume proportion of the alumina-silica type short reinforcing fibers increased above 40%, and particularly when said volume proportion of said alumina-silica type short reinforcing fibers increased above 50%, the bending strength of the composite material did not increase very much even with further increase in the fiber volume proportion. From these results described above, it is seen that in a composite material having alumina-silica type short fiber reinforcing material and having as matrix metal an Al-Cu-Mg type aluminum alloy, said Al-Cu-Mg type aluminum alloy matrix metal having a copper content in the range of from approximately 1.5% to approximately 6%, a magnesium content in the range of from approximately 0.5% to approximately 2%, and remainder substantially aluminum, irrespective of the actual type of the reinforcing alumina-silica fibers utilized, it is preferable that the fiber volume proportion of said alumina-silica type short fiber reinforcing material should be in the range of from approximately 5% to approximately 50%, and more preferably should be in the range of from approximately 5% to approximately 40%.

THE EIGHTEENTH SET OF PREFERRED EMBODIMENTS Variation of mullite crystalline proportion

In the particular case that crystalline alumina-silica short fiber material is used as the alumina-silica type short fiber material for reinforcement, in order to assess what value of the mullite crystalline amount of the crystalline alumina-silica short fiber material yields a high value for the bending strength of the composite material, a number of samples of crystalline alumina-silica type short fiber material were formed in a per se known way: a first set of five thereof having proportion of Al₂ O₃ of approximately 67% and balance SiO₂ and having average fiber length of approximately 0.8 mm and average fiber diameter of approximately 2.6 microns and including samples with mullite crystalline amount of 0%, 20%, 40%, 60%, and 80%; a second set of five thereof having the same proportion of Al₂ O₃ of approximately 67% and balance SiO₂ but having average fiber length of approximately 0.3 mm with the same average fiber diameter of approximately 2.6 microns and likewise including samples with mullite crystalline amount of 0 %, 20%, 40%, 60%, and 80%; a third set of five thereof having proportion of Al₂ O₃ approximately 72% and balance SiO₂ and having average fiber length of approximately 1.0 mm with average fiber diameter of approximately 3.0 microns and likewise including samples with mullite crystalline amount of 0%, 20%, 40%, 60%, and 80%; a fourth set of five thereof having the same proportion of Al₂ O₃ of approximately 72% and balance SiO₂ and having a like average fiber length of approximately 1.0 mm with a like average fiber diameter of approximately 3.0 microns and likewise including samples with mullite crystalline amounts of 0%, 20%, 40%, 60%, and 80%; a fifth set of five thereof having proportion of Al₂ O₃ of approximately 77% and balance SiO₂ and having average fiber length of approximately 1.5 mm and average fiber diameter of approximately 3.2 microns and including samples with mullite crystalline amounts of 0%, 20%, 40%, 60%, and 80%; and a sixth set of five thereof having the same proportion of Al₂ O₃ of approximately 77% and balance SiO₂ but having average fiber length of approximately 0.5 mm with the same average fiber diameter of approximately 3.2 microns and likewise including samples with mullite crystalline amounts of 0%, 20%, 40%, 60%, and 80%. Then, from each of these thirty crystalline alumina-silica type short fiber material samples, a preform was formed in the same manner and under the same conditions as in the seven sets of preferred embodiments detailed above. The fifteen such preforms formed from the first, the third, and the fifth sets of five preforms each were formed with a fiber volume proportion of approximately 10%, and will be referred to as D0 through D4, F0 through F4, and H0 through H4 respectively; and the fifteen such preforms formed from the second, the fourth, and the sixth sets of five preforms each were formed with a fiber volume proportion of approximately 30%, and will be referred to as E0 through E4, G0 through G4, and I0 through I4 respectively. Then, using as matrix metal each such preform as a reinforcing fiber mass and an aluminum alloy of which the copper content was approximately 4%, the magnesium content was approximately 2%, and the remainder was substantially aluminum, various composite material sample pieces were manufactured in the same manner and under the same conditions as in the seven sets of preferred embodiments detailed above, the various resulting composite material sample pieces were subjected to liquidizing processing and artificial aging processing in the same manner and under the same conditions as in the various sets of preferred embodiments detailed above, from each composite material sample piece a bending test piece was cut in the same manner and under the same conditions as in the various sets of preferred embodiments detailed above, and for each bending test piece a bending test was carried out, as before. The results of these bending tests are shown in FIG. 32. It should be noted that in FIG. 32 the mullite crystalline amount (in percent) of the crystalline alumina-silica short fiber material which was the reinforcing fiber material for the composite material test pieces is shown along the horizontal axis, while the bending strength of said composite material test pieces is shown along the vertical axis.

From FIG. 32 it will be seen that, in the case that such an aluminum alloy as detailed above is utilized as the matrix metal, even when the mullite crystalline amount included in the reinforcing fibers is relatively low, the bending strength of the resulting composite material has a relatively high value, and, whatever be the variation in the mullite crystalline amount included in the reinforcing fibers, the variation in the bending strength of the resulting composite material is relatively low. Therefore it will again be seen that, in the case that crystalline alumina-silica short fiber material is used as the alumina-silica short fiber material for reinforcing the material of the present invention, it is acceptable for the value of the mullite crystalline amount therein to be more or less any value.

CONCLUSION

Although the present invention has been shown and described in terms of the preferred embodiments thereof, and with reference to the appended drawings, it should not be considered as being particularly limited thereby, since the details of any particular embodiment, or of the drawings, could be varied without, in many cases, departing from the ambit of the present invention. Accordingly, the scope of the present invention is to be considered as being delimited, not by any particular perhaps entirely fortuitous details of the disclosed preferred embodiments, or of the drawings, but solely by the scope of the accompanying claims, which follow after the Tables.

              TABLE 1                                                     
______________________________________                                    
              COPPER     MAGNESIUM                                        
              CONTENT    CONTENT                                          
ALLOY NO.     (WT %)     (WT %)                                           
______________________________________                                    
A1            1.54       0.04                                             
A2            1.53       0.51                                             
A3            1.51       1.02                                             
A4            1.50       2.00                                             
A5            1.48       2.98                                             
A6            1.47       3.46                                             
A7            1.47       3.99                                             
A8            2.02       0.03                                             
A9            2.02       0.52                                             
A10           1.99       0.96                                             
A11           1.98       1.98                                             
A12           1.96       3.01                                             
A13           1.95       3.47                                             
A14           1.95       4.04                                             
A15           3.03       0.03                                             
A16           3.02       0.48                                             
A17           3.01       0.97                                             
A18           2.99       1.98                                             
A19           2.98       3.01                                             
A20           2.98       3.52                                             
A21           2.96       4.03                                             
A22           4.04       0.01                                             
A23           4.03       0.51                                             
A24           4.01       0.98                                             
A25           3.98       1.97                                             
A26           3.97       3.00                                             
A27           3.97       3.51                                             
A28           3.95       3.99                                             
A29           5.04       0.04                                             
A30           5.03       0.52                                             
A31           5.02       0.96                                             
A32           5.01       2.01                                             
A33           4.96       3.03                                             
A34           4.95       3.49                                             
A35           4.95       3.97                                             
A36           5.54       0.02                                             
A37           5.54       0.53                                             
A38           5.52       1.01                                             
A39           5.51       2.02                                             
A40           5.49       2.97                                             
A41           5.47       3.03                                             
A42           5.45       4.01                                             
A43           6.03       0.02                                             
A44           6.03       0.47                                             
A45           6.03       0.99                                             
A46           6.01       2.00                                             
A47           6.00       2.98                                             
A48           5.96       3.51                                             
A49           5.96       4.01                                             
A50           6.52       0.03                                             
A51           6.51       0.51                                             
A52           6.49       0.99                                             
A53           6.47       2.03                                             
A54           6.47       3.04                                             
A55           6.47       3.52                                             
A56           6.45       3.96                                             
______________________________________

              TABLE 2                                                     
______________________________________                                    
AL-                                                                       
LOY   ALUMINA-SILICA FIBER VOLUME PROPORTION                              
NO.   5%        10%      20%    30%    40%                                
______________________________________                                    
A1    37        40       43     47     53                                 
A2    45        47       50     53     59                                 
A3    47        49       51     56     60                                 
A4    48        51       52     58     63                                 
A5    49        52       53     59     64                                 
A6    47        49       51     55     61                                 
A7    41        43       45     49     57                                 
A8    38        41       45     50     55                                 
A9    51        55       60     64     68                                 
A10   54        56       63     65     70                                 
A11   56        59       65     68     73                                 
A12   57        60       64     70     75                                 
A13   53        56       62     65     71                                 
A14   45        46       50     51     60                                 
A15   40        45       52     59     67                                 
A16   55        59       63     66     71                                 
A17   58        61       65     68     73                                 
A18   60        62       66     71     76                                 
A19   60        62       67     72     77                                 
A20   55        57       63     65     71                                 
A21   46        47       49     52     60                                 
A22   43        49       55     65     67                                 
A23   57        61       65     69     73                                 
A24   60        63       68     71     75                                 
A25   62        65       69     74     78                                 
A26   61        64       69     74     78                                 
A27   55        58       64     67     72                                 
A28   45        47       50     53     61                                 
A29   46        52       59     64     61                                 
A30   58        61       66     68     71                                 
A31   61        63       68     69     72                                 
A32   63        66       70     73     77                                 
A33   61        63       68     71     77                                 
A34   54        57       63     64     71                                 
A35   44        46       52     52     59                                 
A36   48        53       60     61     64                                 
A37   57        60       65     67     69                                 
A38   59        62       67     68     71                                 
A39   61        63       69     71     74                                 
A40   59        62       67     70     73                                 
A41   53        56       62     65     69                                 
A42   44        45       51     52     59                                 
A43   50        55       60     60     59                                 
A44   53        57       62     62     64                                 
A45   55        58       63     64     67                                 
A46   56        60       63     65     69                                 
A47   54        59       62     64     68                                 
A48   52        56       60     60     65                                 
A49   43        44       52     50     56                                 
A50   47        53       55     58     57                                 
A51   48        53       55     59     59                                 
A52   49        54       56     60     61                                 
A53   49        54       57     60     62                                 
A54   48        51       56     59     60                                 
A55   47        49       54     55     58                                 
A56   42        43       48     49     54                                 
______________________________________

              TABLE 3                                                     
______________________________________                                    
            ALUMINA-SILICA FIBER                                          
ALLOY       VOLUME PROPORTION                                             
NO.         30%         10%                                               
______________________________________                                    
A1          45          37                                                
A2          53          45                                                
A3          55          47                                                
A4          57          49                                                
A5          59          51                                                
A6          57          48                                                
A7          48          42                                                
A8          46          39                                                
A9          63          55                                                
A10         64          56                                                
A11         67          58                                                
A12         69          59                                                
A13         64          54                                                
A14         50          45                                                
A15         57          42                                                
A16         65          58                                                
A17         67          60                                                
A18         70          61                                                
A19         71          61                                                
A20         64          55                                                
A21         51          46                                                
A22         63          47                                                
A23         68          60                                                
A24         70          62                                                
A25         73          64                                                
A26         73          63                                                
A27         67          56                                                
A28         54          56                                                
A29         64          51                                                
A30         68          60                                                
A31         69          62                                                
A32         72          65                                                
A33         70          62                                                
A34         63          65                                                
A35         50          44                                                
A36         62          52                                                
A37         66          59                                                
A38         68          61                                                
A39         70          62                                                
A40         69          60                                                
A41         63          54                                                
A42         51          43                                                
A43         60          54                                                
A44         62          56                                                
A45         63          57                                                
A46         65          60                                                
A47         63          58                                                
A48         60          54                                                
A49         49          43                                                
A50         57          53                                                
A51         58          53                                                
A52         58          54                                                
A53         59          54                                                
A54         58          52                                                
A55         57          48                                                
A56         49          42                                                
______________________________________

              TABLE 4                                                     
______________________________________                                    
            ALUMINA-SILICA FIBER                                          
ALLOY       VOLUME PROPORTION                                             
NO.         30%         10%                                               
______________________________________                                    
A1          43          36                                                
A2          50          45                                                
A3          52          48                                                
A4          54          50                                                
A5          55          51                                                
A6          53          47                                                
A7          46          41                                                
A8          46          39                                                
A9          61          53                                                
A10         62          54                                                
A11         65          57                                                
A12         68          58                                                
A13         63          53                                                
A14         49          43                                                
A15         53          41                                                
A16         63          57                                                
A17         66          58                                                
A18         69          60                                                
A19         71          61                                                
A20         63          54                                                
A21         51          44                                                
A22         60          45                                                
A23         67          59                                                
A24         69          61                                                
A25         72          63                                                
A26         72          62                                                
A27         65          55                                                
A28         51          44                                                
A29         61          50                                                
A30         67          59                                                
A31         68          60                                                
A32         70          64                                                
A33         69          60                                                
A34         62          53                                                
A35         48          42                                                
A36         59          51                                                
A37         65          58                                                
A38         67          59                                                
A39         69          61                                                
A40         67          60                                                
A41         61          52                                                
A42         48          41                                                
A43         56          53                                                
A44         59          55                                                
A45         61          56                                                
A46         62          59                                                
A47         61          57                                                
A48         58          54                                                
A49         47          42                                                
A50         53          51                                                
A51         54          51                                                
A52         55          52                                                
A53         56          52                                                
A54         54          51                                                
A55         52          47                                                
A56         43          40                                                
______________________________________

              TABLE 5                                                     
______________________________________                                    
AL-                                                                       
LOY   ALUMINA-SILICA FIBER VOLUME PROPORTION                              
NO.   5%        10%      20%    30%    40%                                
______________________________________                                    
A1    35        37       40     43     46                                 
A2    43        45       49     50     52                                 
A3    45        47       52     52     56                                 
A4    47        49       53     53     58                                 
A5    45        47       51     51     54                                 
A6    40        43       49     48     50                                 
A7    36        40       45     43     46                                 
A8    36        48       41     44     49                                 
A9    52        54       56     58     65                                 
A10   54        56       62     63     69                                 
A11   55        57       64     65     71                                 
A12   52        54       58     60     66                                 
A13   49        49       56     56     58                                 
A14   41        42       49     46     49                                 
A15   38        40       47     51     53                                 
A16   54        57       62     64     68                                 
A17   55        59       64     66     71                                 
A18   56        60       65     67     72                                 
A19   52        56       58     61     67                                 
A20   48        50       55     57     59                                 
A21   40        43       48     45     48                                 
A22   43        45       52     57     60                                 
A23   57        59       64     68     69                                 
A24   59        62       66     70     72                                 
A25   59        62       66     70     72                                 
A26   54        57       59     62     65                                 
A27   50        53       55     58     58                                 
A28   41        43       47     46     47                                 
A29   47        49       55     58     59                                 
A30   57        59       65     68     70                                 
A31   59        62       66     71     73                                 
A32   58        60       65     69     71                                 
A33   53        55       57     62     65                                 
A34   48        49       50     56     58                                 
A35   39        42       46     45     47                                 
A36   49        51       56     54     56                                 
A37   56        58       64     66     67                                 
A38   58        61       65     67     70                                 
A39   56        58       62     66     68                                 
A40   52        54       56     60     63                                 
A41   47        46       53     55     55                                 
A42   39        41       45     44     47                                 
A43   51        52       53     52     52                                 
A44   53        55       58     56     60                                 
A45   54        57       60     61     63                                 
A46   53        55       58     59     62                                 
A47   51        53       53     55     60                                 
A48   46        47       50     49     51                                 
A49   38        41       45     44     46                                 
A50   49        52       50     50     45                                 
A51   50        55       53     53     50                                 
A52   50        57       54     54     51                                 
A53   49        55       53     52     50                                 
A54   47        53       50     49     49                                 
A55   41        44       48     47     47                                 
A56   38        40       44     43     45                                 
______________________________________

              TABLE 6                                                     
______________________________________                                    
AL-                                                                       
LOY   ALUMINA-SILICA FIBER VOLUME PROPORTION                              
NO.   5%        10%      20%    30%    40%                                
______________________________________                                    
A1    38        41       45     48     51                                 
A2    43        46       49     50     53                                 
A3    44        47       50     51     54                                 
A4    48        52       54     57     58                                 
A5    49        53       55     58     59                                 
A6    48        50       52     57     57                                 
A7    39        43       44     53     51                                 
A8    40        43       47     51     55                                 
A9    50        53       55     59     62                                 
A10   51        54       56     60     63                                 
A11   56        58       61     68     72                                 
A12   57        59       62     71     74                                 
A13   56        57       57     68     72                                 
A14   40        45       46     57     52                                 
A15   44        47       51     60     63                                 
A16   52        55       58     66     68                                 
A17   52        55       59     67     69                                 
A18   59        61       66     73     75                                 
A19   59        62       67     74     76                                 
A20   57        59       62     71     72                                 
A21   39        44       46     57     52                                 
A22   46        50       55     66     68                                 
A23   54        57       60     70     72                                 
A24   54        58       62     71     72                                 
A25   61        64       70     76     79                                 
A26   62        65       71     75     78                                 
A27   59        61       65     70     72                                 
A28   38        45       45     56     50                                 
A29   50        53       58     65     66                                 
A30   55        58       62     69     70                                 
A31   56        68       63     70     71                                 
A32   63        65       72     74     77                                 
A33   62        65       72     74     76                                 
A34   58        60       66     71     71                                 
A35   37        44       47     46     50                                 
A36   51        54       59     62     64                                 
A37   55        57       62     67     69                                 
A38   55        57       62     68     69                                 
A39   61        63       69     74     74                                 
A40   60        63       69     73     73                                 
A41   58        59       63     69     70                                 
A42   38        43       46     55     51                                 
A43   53        56       60     61     63                                 
A44   54        57       61     62     64                                 
A45   54        57       61     62     64                                 
A46   58        61       65     65     67                                 
A47   57        61       64     64     66                                 
A48   56        57       62     61     64                                 
A49   39        48       45     55     54                                 
A50   49        53       54     58     60                                 
A51   49        53       54     58     61                                 
A52   49        53       54     58     61                                 
A53   48        52       53     59     63                                 
A54   46        50       51     58     62                                 
A55   44        48       49     56     59                                 
A56   37        42       48     51     52                                 
______________________________________

              TABLE 7                                                     
______________________________________                                    
            ALUMINA-SILICA FIBER                                          
ALLOY       VOLUME PROPORTION                                             
NO.         30%         10%                                               
______________________________________                                    
A1          39          45                                                
A2          43          47                                                
A3          44          48                                                
A4          48          52                                                
A5          49          53                                                
A6          48          51                                                
A7          40          44                                                
A8          41          48                                                
A9          51          57                                                
A10         52          58                                                
A11         57          64                                                
A12         58          65                                                
A13         55          63                                                
A14         39          45                                                
A15         45          56                                                
A16         53          62                                                
A17         53          62                                                
A18         59          68                                                
A19         59          68                                                
A20         56          64                                                
A21         38          47                                                
A22         47          61                                                
A23         55          65                                                
A24         55          66                                                
A25         62          71                                                
A26         61          71                                                
A27         57          65                                                
A28         39          50                                                
A29         51          60                                                
A30         56          63                                                
A31         57          63                                                
A32         63          70                                                
A33         61          69                                                
A34         56          64                                                
A35         38          46                                                
A36         52          57                                                
A37         56          62                                                
A38         56          63                                                
A39         62          68                                                
A40         60          67                                                
A41         55          63                                                
A42         38          48                                                
A43         52          56                                                
A44         55          58                                                
A45         55          58                                                
A46         58          62                                                
A47         57          60                                                
A48         54          56                                                
A49         38          45                                                
A50         51          55                                                
A51         51          55                                                
A52         51          55                                                
A53         50          57                                                
A54         48          54                                                
A55         46          51                                                
A56         39          44                                                
______________________________________

              TABLE 8                                                     
______________________________________                                    
AL-   ALUMINA-SILICA FIBER VOLUME PROPORTION                              
LOY   I          II         III     IV                                    
NO.   5%         10%        20%     30%                                   
______________________________________                                    
A1    42         46         47      38                                    
A2    46         48         49      42                                    
A3    47         48         50      43                                    
A4    52         52         56      47                                    
A5    53         53         57      47                                    
A6    50         52         56      46                                    
A7    43         45         50      39                                    
A8    42         49         51      40                                    
A9    52         58         59      51                                    
A10   55         59         60      52                                    
A11   59         65         58      57                                    
A12   60         65         69      57                                    
A13   59         63         68      56                                    
A14   47         47         51      38                                    
A15   47         56         59      44                                    
A16   55         62         65      52                                    
A17   55         63         66      53                                    
A18   62         68         72      58                                    
A19   62         68         72      58                                    
A20   60         64         69      56                                    
A21   46         46         51      37                                    
A22   51         61         65      46                                    
A23   57         65         68      54                                    
A24   58         65         68      54                                    
A25   64         71         73      62                                    
A26   65         70         72      59                                    
A27   61         64         68      55                                    
A28   46         45         49      47                                    
A29   53         60         64      50                                    
A30   58         63         67      55                                    
A31   59         63         68      55                                    
A32   66         69         71      61                                    
A33   65         68         71      58                                    
A34   60         63         67      54                                    
A35   45         44         49      36                                    
A36   54         57         61      51                                    
A37   57         62         65      54                                    
A38   57         63         65      54                                    
A39   63         67         70      59                                    
A40   62         66         59      57                                    
A41   59         62         56      64                                    
A42   44         43         48      37                                    
A43   56         56         59      63                                    
A44   58         58         61      54                                    
A45   58         58         61      54                                    
A46   62         62         63      58                                    
A47   61         61         63      57                                    
A48   58         59         62      54                                    
A49   44         46         50      36                                    
A50   53         55         57      50                                    
A51   53         56         58      51                                    
A52   53         56         58      51                                    
A53   54         57         58      50                                    
A54   51         55         57      47                                    
A55   48         51         54      43                                    
A56   43         42         47      35                                    
______________________________________

Claims

What is claimed is:

1. A composite material comprising a mass of alumina-silica short fibers embedded in a matrix of metal, said alumina-silica short fibers having a composition of from about 35% to about 80% of Al₂ O₃ and from about 65% to about 20% of SiO₂ with less than about 10% of other included constituents; said matrix metal being an alloy consisting essentially of from more than 45% to 6% of copper, from more than 2% to approximately 3.5% of magnesium, and remainder substantially aluminum; and the volume proportion of said alumina-silica short fibers being from about 5% to about 50%.

2. A composite material according to claim 1, wherein said alumina-silica short fibers have a composition of from about 35% to about 65% of Al₂ O₃ and from about 65% to about 35% of SiO₂ with less than about 10% of other included constituents.

3. A composite material according to claim 1, wherein said alumina-silica short fibers have a composition of from about 65% to about 80% of Al₂ O₃ and from about 35% to about 20% of SiO₂ with less than about 10% of other included constituents.

4. A composite material according to claim 1, wherein the volume proportion of said alumina-silica short fibers being from about 5% to about 40%.

5. A composite material according to claim 2, wherein the volume proportion of said alumina-silica short fibers being from about 5% to about 40%.

6. A composite material according to claim 3, wherein the volume proportion of said alumina-silica short fibers being from about 5% to about 40%.

7. A composite material comprising a mass of alumina-silica short fibers embedded in a matrix of metal, said alumina-silica short fibers having a composition of from about 35% to about 80% of Al₂ O₃ and from about 65% to about 20% of SiO₂ with less than about 10% of other included constituents; said matrix metal being an alloy consisting essentially of from approximately 5% to approximately 6% of copper, from approximately 2.0% to approximately 3.5% of magnesium, and remainder substantially aluminum and the volume proportion of said alumina-silica short fibers being from about 5% to about 50%.

8. The composite material of claim 7, wherein said alumina-silica short fibers have a composition of from about 35% to about 65% of Al₂ O₃ and from about 65% to about 35% of SiO₂ with less than about 10% of other included constituents.

9. The composite material of claim 7, wherein said alumina-silica short fibers have a composition of from about 65% to about 80% of Al₂ O₃ and from about 35% to about 20% of SiO₂ with less than about 10% of other included constituents.

10. The composite material according to claim 7, wherein the volume proportion of said alumina-silica short fibers is from about 5% to about 40%.

11. The composite material of claim 8, wherein the volume proportion of said alumina-silica short fibers is from about 5% to about 40%.

12. The composite material of claim 9, wherein the volume proportion of said alumina-silica short fibers is from about 5% to about 40%.

13. A composite material comprising a mass of alumina-silica short fibers embedded in a matrix of metal, said alumina-silica short fibers having a composition of from 35% to about 80% of Al₂ O₃ and from about 65% to about 20% of SiO₂ with less than about 10% of other included constituents; said matrix metal being an alloy consisting of from approximately 2% to approximately 6% of copper, from approximately 0.5% to approximately 3.5% of magnesium, and the remainder substantially aluminum; and the volume proportion of said alumina-silica short fibers being from about 5% to about 50%.

14. The composite material of claim 13, wherein said alumina-silica short fibers have a composition of from about 35% to about 60% of Al₂ O₃ and from about 65% to about 35% of SiO₂ with less than about 10% of other included constituents.

15. The composite material of claim 13, wherein said alumina-silica short fibers have a composition of from about 65% to about 80% of Al₂ O₃ and from about 35% to about 20% of SiO₂ with less than about 10% of other included constituents.

16. The composite material of claim 13, wherein the volume proportion of said alumina-silica short fibers is from about 5% to about 40%.

17. The composite material of claim 14, wherein the volume proportion of said alumina-silica fibers is from about 5% to about 40%.

18. The composite material of claim 15, wherein the volume proportion of said alumina-silica short fibers is from about 5% to about 40%.